2 # (C) Copyright 2000 - 2008
3 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 # See file CREDITS for list of people who contributed to this
8 # This program is free software; you can redistribute it and/or
9 # modify it under the terms of the GNU General Public License as
10 # published by the Free Software Foundation; either version 2 of
11 # the License, or (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with this program; if not, write to the Free Software
20 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
27 This directory contains the source code for U-Boot, a boot loader for
28 Embedded boards based on PowerPC, ARM, MIPS and several other
29 processors, which can be installed in a boot ROM and used to
30 initialize and test the hardware or to download and run application
33 The development of U-Boot is closely related to Linux: some parts of
34 the source code originate in the Linux source tree, we have some
35 header files in common, and special provision has been made to
36 support booting of Linux images.
38 Some attention has been paid to make this software easily
39 configurable and extendable. For instance, all monitor commands are
40 implemented with the same call interface, so that it's very easy to
41 add new commands. Also, instead of permanently adding rarely used
42 code (for instance hardware test utilities) to the monitor, you can
43 load and run it dynamically.
49 In general, all boards for which a configuration option exists in the
50 Makefile have been tested to some extent and can be considered
51 "working". In fact, many of them are used in production systems.
53 In case of problems see the CHANGELOG and CREDITS files to find out
54 who contributed the specific port. The MAINTAINERS file lists board
61 In case you have questions about, problems with or contributions for
62 U-Boot you should send a message to the U-Boot mailing list at
63 <u-boot-users@lists.sourceforge.net>. There is also an archive of
64 previous traffic on the mailing list - please search the archive
65 before asking FAQ's. Please see
66 http://lists.sourceforge.net/lists/listinfo/u-boot-users/
69 Where to get source code:
70 =========================
72 The U-Boot source code is maintained in the git repository at
73 git://www.denx.de/git/u-boot.git ; you can browse it online at
74 http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=summary
76 The "snapshot" links on this page allow you to download tarballs of
77 any version you might be interested in. Ofifcial releases are also
78 available for FTP download from the ftp://ftp.denx.de/pub/u-boot/
81 Pre-built (and tested) images are available from
82 ftp://ftp.denx.de/pub/u-boot/images/
88 - start from 8xxrom sources
89 - create PPCBoot project (http://sourceforge.net/projects/ppcboot)
91 - make it easier to add custom boards
92 - make it possible to add other [PowerPC] CPUs
93 - extend functions, especially:
94 * Provide extended interface to Linux boot loader
97 * PCMCIA / CompactFLash / ATA disk / SCSI ... boot
98 - create ARMBoot project (http://sourceforge.net/projects/armboot)
99 - add other CPU families (starting with ARM)
100 - create U-Boot project (http://sourceforge.net/projects/u-boot)
101 - current project page: see http://www.denx.de/wiki/UBoot
107 The "official" name of this project is "Das U-Boot". The spelling
108 "U-Boot" shall be used in all written text (documentation, comments
109 in source files etc.). Example:
111 This is the README file for the U-Boot project.
113 File names etc. shall be based on the string "u-boot". Examples:
115 include/asm-ppc/u-boot.h
117 #include <asm/u-boot.h>
119 Variable names, preprocessor constants etc. shall be either based on
120 the string "u_boot" or on "U_BOOT". Example:
122 U_BOOT_VERSION u_boot_logo
123 IH_OS_U_BOOT u_boot_hush_start
129 U-Boot uses a 3 level version number containing a version, a
130 sub-version, and a patchlevel: "U-Boot-2.34.5" means version "2",
131 sub-version "34", and patchlevel "4".
133 The patchlevel is used to indicate certain stages of development
134 between released versions, i. e. officially released versions of
135 U-Boot will always have a patchlevel of "0".
141 - board Board dependent files
142 - common Misc architecture independent functions
143 - cpu CPU specific files
144 - 74xx_7xx Files specific to Freescale MPC74xx and 7xx CPUs
145 - arm720t Files specific to ARM 720 CPUs
146 - arm920t Files specific to ARM 920 CPUs
147 - at91rm9200 Files specific to Atmel AT91RM9200 CPU
148 - imx Files specific to Freescale MC9328 i.MX CPUs
149 - s3c24x0 Files specific to Samsung S3C24X0 CPUs
150 - arm925t Files specific to ARM 925 CPUs
151 - arm926ejs Files specific to ARM 926 CPUs
152 - arm1136 Files specific to ARM 1136 CPUs
153 - at32ap Files specific to Atmel AVR32 AP CPUs
154 - i386 Files specific to i386 CPUs
155 - ixp Files specific to Intel XScale IXP CPUs
156 - leon2 Files specific to Gaisler LEON2 SPARC CPU
157 - leon3 Files specific to Gaisler LEON3 SPARC CPU
158 - mcf52x2 Files specific to Freescale ColdFire MCF52x2 CPUs
159 - mcf5227x Files specific to Freescale ColdFire MCF5227x CPUs
160 - mcf532x Files specific to Freescale ColdFire MCF5329 CPUs
161 - mcf5445x Files specific to Freescale ColdFire MCF5445x CPUs
162 - mcf547x_8x Files specific to Freescale ColdFire MCF547x_8x CPUs
163 - mips Files specific to MIPS CPUs
164 - mpc5xx Files specific to Freescale MPC5xx CPUs
165 - mpc5xxx Files specific to Freescale MPC5xxx CPUs
166 - mpc8xx Files specific to Freescale MPC8xx CPUs
167 - mpc8220 Files specific to Freescale MPC8220 CPUs
168 - mpc824x Files specific to Freescale MPC824x CPUs
169 - mpc8260 Files specific to Freescale MPC8260 CPUs
170 - mpc85xx Files specific to Freescale MPC85xx CPUs
171 - nios Files specific to Altera NIOS CPUs
172 - nios2 Files specific to Altera Nios-II CPUs
173 - ppc4xx Files specific to AMCC PowerPC 4xx CPUs
174 - pxa Files specific to Intel XScale PXA CPUs
175 - s3c44b0 Files specific to Samsung S3C44B0 CPUs
176 - sa1100 Files specific to Intel StrongARM SA1100 CPUs
177 - disk Code for disk drive partition handling
178 - doc Documentation (don't expect too much)
179 - drivers Commonly used device drivers
180 - dtt Digital Thermometer and Thermostat drivers
181 - examples Example code for standalone applications, etc.
182 - include Header Files
183 - lib_arm Files generic to ARM architecture
184 - lib_avr32 Files generic to AVR32 architecture
185 - lib_generic Files generic to all architectures
186 - lib_i386 Files generic to i386 architecture
187 - lib_m68k Files generic to m68k architecture
188 - lib_mips Files generic to MIPS architecture
189 - lib_nios Files generic to NIOS architecture
190 - lib_ppc Files generic to PowerPC architecture
191 - lib_sparc Files generic to SPARC architecture
192 - libfdt Library files to support flattened device trees
193 - net Networking code
194 - post Power On Self Test
195 - rtc Real Time Clock drivers
196 - tools Tools to build S-Record or U-Boot images, etc.
198 Software Configuration:
199 =======================
201 Configuration is usually done using C preprocessor defines; the
202 rationale behind that is to avoid dead code whenever possible.
204 There are two classes of configuration variables:
206 * Configuration _OPTIONS_:
207 These are selectable by the user and have names beginning with
210 * Configuration _SETTINGS_:
211 These depend on the hardware etc. and should not be meddled with if
212 you don't know what you're doing; they have names beginning with
215 Later we will add a configuration tool - probably similar to or even
216 identical to what's used for the Linux kernel. Right now, we have to
217 do the configuration by hand, which means creating some symbolic
218 links and editing some configuration files. We use the TQM8xxL boards
222 Selection of Processor Architecture and Board Type:
223 ---------------------------------------------------
225 For all supported boards there are ready-to-use default
226 configurations available; just type "make <board_name>_config".
228 Example: For a TQM823L module type:
233 For the Cogent platform, you need to specify the cpu type as well;
234 e.g. "make cogent_mpc8xx_config". And also configure the cogent
235 directory according to the instructions in cogent/README.
238 Configuration Options:
239 ----------------------
241 Configuration depends on the combination of board and CPU type; all
242 such information is kept in a configuration file
243 "include/configs/<board_name>.h".
245 Example: For a TQM823L module, all configuration settings are in
246 "include/configs/TQM823L.h".
249 Many of the options are named exactly as the corresponding Linux
250 kernel configuration options. The intention is to make it easier to
251 build a config tool - later.
254 The following options need to be configured:
256 - CPU Type: Define exactly one, e.g. CONFIG_MPC85XX.
258 - Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS.
260 - CPU Daughterboard Type: (if CONFIG_ATSTK1000 is defined)
261 Define exactly one, e.g. CONFIG_ATSTK1002
263 - CPU Module Type: (if CONFIG_COGENT is defined)
264 Define exactly one of
266 --- FIXME --- not tested yet:
267 CONFIG_CMA286_60, CONFIG_CMA286_21, CONFIG_CMA286_60P,
268 CONFIG_CMA287_23, CONFIG_CMA287_50
270 - Motherboard Type: (if CONFIG_COGENT is defined)
271 Define exactly one of
272 CONFIG_CMA101, CONFIG_CMA102
274 - Motherboard I/O Modules: (if CONFIG_COGENT is defined)
275 Define one or more of
278 - Motherboard Options: (if CONFIG_CMA101 or CONFIG_CMA102 are defined)
279 Define one or more of
280 CONFIG_LCD_HEARTBEAT - update a character position on
281 the lcd display every second with
284 - Board flavour: (if CONFIG_MPC8260ADS is defined)
287 CFG_8260ADS - original MPC8260ADS
288 CFG_8266ADS - MPC8266ADS
289 CFG_PQ2FADS - PQ2FADS-ZU or PQ2FADS-VR
290 CFG_8272ADS - MPC8272ADS
292 - MPC824X Family Member (if CONFIG_MPC824X is defined)
293 Define exactly one of
294 CONFIG_MPC8240, CONFIG_MPC8245
296 - 8xx CPU Options: (if using an MPC8xx cpu)
297 CONFIG_8xx_GCLK_FREQ - deprecated: CPU clock if
298 get_gclk_freq() cannot work
299 e.g. if there is no 32KHz
300 reference PIT/RTC clock
301 CONFIG_8xx_OSCLK - PLL input clock (either EXTCLK
304 - 859/866/885 CPU options: (if using a MPC859 or MPC866 or MPC885 CPU):
307 CONFIG_8xx_CPUCLK_DEFAULT
308 See doc/README.MPC866
312 Define this to measure the actual CPU clock instead
313 of relying on the correctness of the configured
314 values. Mostly useful for board bringup to make sure
315 the PLL is locked at the intended frequency. Note
316 that this requires a (stable) reference clock (32 kHz
317 RTC clock or CFG_8XX_XIN)
319 - Intel Monahans options:
320 CFG_MONAHANS_RUN_MODE_OSC_RATIO
322 Defines the Monahans run mode to oscillator
323 ratio. Valid values are 8, 16, 24, 31. The core
324 frequency is this value multiplied by 13 MHz.
326 CFG_MONAHANS_TURBO_RUN_MODE_RATIO
328 Defines the Monahans turbo mode to oscillator
329 ratio. Valid values are 1 (default if undefined) and
330 2. The core frequency as calculated above is multiplied
333 - Linux Kernel Interface:
336 U-Boot stores all clock information in Hz
337 internally. For binary compatibility with older Linux
338 kernels (which expect the clocks passed in the
339 bd_info data to be in MHz) the environment variable
340 "clocks_in_mhz" can be defined so that U-Boot
341 converts clock data to MHZ before passing it to the
343 When CONFIG_CLOCKS_IN_MHZ is defined, a definition of
344 "clocks_in_mhz=1" is automatically included in the
347 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only]
349 When transfering memsize parameter to linux, some versions
350 expect it to be in bytes, others in MB.
351 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes.
353 CONFIG_OF_LIBFDT / CONFIG_OF_FLAT_TREE
355 New kernel versions are expecting firmware settings to be
356 passed using flattened device trees (based on open firmware
360 * New libfdt-based support
361 * Adds the "fdt" command
362 * The bootm command automatically updates the fdt
365 * Deprecated, see CONFIG_OF_LIBFDT
366 * Original ft_build.c-based support
367 * Automatically modifies the dft as part of the bootm command
368 * The environment variable "disable_of", when set,
369 disables this functionality.
371 OF_CPU - The proper name of the cpus node.
372 OF_SOC - The proper name of the soc node.
373 OF_TBCLK - The timebase frequency.
374 OF_STDOUT_PATH - The path to the console device
376 boards with QUICC Engines require OF_QE to set UCC mac addresses
378 CONFIG_OF_BOARD_SETUP
380 Board code has addition modification that it wants to make
381 to the flat device tree before handing it off to the kernel
385 This define fills in the correct boot cpu in the boot
386 param header, the default value is zero if undefined.
391 Define this if you want support for Amba PrimeCell PL010 UARTs.
395 Define this if you want support for Amba PrimeCell PL011 UARTs.
399 If you have Amba PrimeCell PL011 UARTs, set this variable to
400 the clock speed of the UARTs.
404 If you have Amba PrimeCell PL010 or PL011 UARTs on your board,
405 define this to a list of base addresses for each (supported)
406 port. See e.g. include/configs/versatile.h
410 Depending on board, define exactly one serial port
411 (like CONFIG_8xx_CONS_SMC1, CONFIG_8xx_CONS_SMC2,
412 CONFIG_8xx_CONS_SCC1, ...), or switch off the serial
413 console by defining CONFIG_8xx_CONS_NONE
415 Note: if CONFIG_8xx_CONS_NONE is defined, the serial
416 port routines must be defined elsewhere
417 (i.e. serial_init(), serial_getc(), ...)
420 Enables console device for a color framebuffer. Needs following
421 defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
422 VIDEO_FB_LITTLE_ENDIAN graphic memory organisation
424 VIDEO_HW_RECTFILL graphic chip supports
427 VIDEO_HW_BITBLT graphic chip supports
428 bit-blit (cf. smiLynxEM)
429 VIDEO_VISIBLE_COLS visible pixel columns
431 VIDEO_VISIBLE_ROWS visible pixel rows
432 VIDEO_PIXEL_SIZE bytes per pixel
433 VIDEO_DATA_FORMAT graphic data format
434 (0-5, cf. cfb_console.c)
435 VIDEO_FB_ADRS framebuffer address
436 VIDEO_KBD_INIT_FCT keyboard int fct
437 (i.e. i8042_kbd_init())
438 VIDEO_TSTC_FCT test char fct
440 VIDEO_GETC_FCT get char fct
442 CONFIG_CONSOLE_CURSOR cursor drawing on/off
443 (requires blink timer
445 CFG_CONSOLE_BLINK_COUNT blink interval (cf. i8042.c)
446 CONFIG_CONSOLE_TIME display time/date info in
448 (requires CONFIG_CMD_DATE)
449 CONFIG_VIDEO_LOGO display Linux logo in
451 CONFIG_VIDEO_BMP_LOGO use bmp_logo.h instead of
452 linux_logo.h for logo.
453 Requires CONFIG_VIDEO_LOGO
454 CONFIG_CONSOLE_EXTRA_INFO
455 addional board info beside
458 When CONFIG_CFB_CONSOLE is defined, video console is
459 default i/o. Serial console can be forced with
460 environment 'console=serial'.
462 When CONFIG_SILENT_CONSOLE is defined, all console
463 messages (by U-Boot and Linux!) can be silenced with
464 the "silent" environment variable. See
465 doc/README.silent for more information.
468 CONFIG_BAUDRATE - in bps
469 Select one of the baudrates listed in
470 CFG_BAUDRATE_TABLE, see below.
471 CFG_BRGCLK_PRESCALE, baudrate prescale
473 - Interrupt driven serial port input:
474 CONFIG_SERIAL_SOFTWARE_FIFO
477 Use an interrupt handler for receiving data on the
478 serial port. It also enables using hardware handshake
479 (RTS/CTS) and UART's built-in FIFO. Set the number of
480 bytes the interrupt driven input buffer should have.
482 Leave undefined to disable this feature, including
483 disable the buffer and hardware handshake.
485 - Console UART Number:
489 If defined internal UART1 (and not UART0) is used
490 as default U-Boot console.
492 - Boot Delay: CONFIG_BOOTDELAY - in seconds
493 Delay before automatically booting the default image;
494 set to -1 to disable autoboot.
496 See doc/README.autoboot for these options that
497 work with CONFIG_BOOTDELAY. None are required.
498 CONFIG_BOOT_RETRY_TIME
499 CONFIG_BOOT_RETRY_MIN
500 CONFIG_AUTOBOOT_KEYED
501 CONFIG_AUTOBOOT_PROMPT
502 CONFIG_AUTOBOOT_DELAY_STR
503 CONFIG_AUTOBOOT_STOP_STR
504 CONFIG_AUTOBOOT_DELAY_STR2
505 CONFIG_AUTOBOOT_STOP_STR2
506 CONFIG_ZERO_BOOTDELAY_CHECK
507 CONFIG_RESET_TO_RETRY
511 Only needed when CONFIG_BOOTDELAY is enabled;
512 define a command string that is automatically executed
513 when no character is read on the console interface
514 within "Boot Delay" after reset.
517 This can be used to pass arguments to the bootm
518 command. The value of CONFIG_BOOTARGS goes into the
519 environment value "bootargs".
521 CONFIG_RAMBOOT and CONFIG_NFSBOOT
522 The value of these goes into the environment as
523 "ramboot" and "nfsboot" respectively, and can be used
524 as a convenience, when switching between booting from
530 When this option is #defined, the existence of the
531 environment variable "preboot" will be checked
532 immediately before starting the CONFIG_BOOTDELAY
533 countdown and/or running the auto-boot command resp.
534 entering interactive mode.
536 This feature is especially useful when "preboot" is
537 automatically generated or modified. For an example
538 see the LWMON board specific code: here "preboot" is
539 modified when the user holds down a certain
540 combination of keys on the (special) keyboard when
543 - Serial Download Echo Mode:
545 If defined to 1, all characters received during a
546 serial download (using the "loads" command) are
547 echoed back. This might be needed by some terminal
548 emulations (like "cu"), but may as well just take
549 time on others. This setting #define's the initial
550 value of the "loads_echo" environment variable.
552 - Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined)
554 Select one of the baudrates listed in
555 CFG_BAUDRATE_TABLE, see below.
558 Monitor commands can be included or excluded
559 from the build by using the #include files
560 "config_cmd_all.h" and #undef'ing unwanted
561 commands, or using "config_cmd_default.h"
562 and augmenting with additional #define's
565 The default command configuration includes all commands
566 except those marked below with a "*".
568 CONFIG_CMD_ASKENV * ask for env variable
569 CONFIG_CMD_AUTOSCRIPT Autoscript Support
570 CONFIG_CMD_BDI bdinfo
571 CONFIG_CMD_BEDBUG * Include BedBug Debugger
572 CONFIG_CMD_BMP * BMP support
573 CONFIG_CMD_BSP * Board specific commands
574 CONFIG_CMD_BOOTD bootd
575 CONFIG_CMD_CACHE * icache, dcache
576 CONFIG_CMD_CONSOLE coninfo
577 CONFIG_CMD_DATE * support for RTC, date/time...
578 CONFIG_CMD_DHCP * DHCP support
579 CONFIG_CMD_DIAG * Diagnostics
580 CONFIG_CMD_DOC * Disk-On-Chip Support
581 CONFIG_CMD_DTT * Digital Therm and Thermostat
582 CONFIG_CMD_ECHO echo arguments
583 CONFIG_CMD_EEPROM * EEPROM read/write support
584 CONFIG_CMD_ELF * bootelf, bootvx
585 CONFIG_CMD_ENV saveenv
586 CONFIG_CMD_FDC * Floppy Disk Support
587 CONFIG_CMD_FAT * FAT partition support
588 CONFIG_CMD_FDOS * Dos diskette Support
589 CONFIG_CMD_FLASH flinfo, erase, protect
590 CONFIG_CMD_FPGA FPGA device initialization support
591 CONFIG_CMD_HWFLOW * RTS/CTS hw flow control
592 CONFIG_CMD_I2C * I2C serial bus support
593 CONFIG_CMD_IDE * IDE harddisk support
594 CONFIG_CMD_IMI iminfo
595 CONFIG_CMD_IMLS List all found images
596 CONFIG_CMD_IMMAP * IMMR dump support
597 CONFIG_CMD_IRQ * irqinfo
598 CONFIG_CMD_ITEST Integer/string test of 2 values
599 CONFIG_CMD_JFFS2 * JFFS2 Support
600 CONFIG_CMD_KGDB * kgdb
601 CONFIG_CMD_LOADB loadb
602 CONFIG_CMD_LOADS loads
603 CONFIG_CMD_MEMORY md, mm, nm, mw, cp, cmp, crc, base,
605 CONFIG_CMD_MISC Misc functions like sleep etc
606 CONFIG_CMD_MMC * MMC memory mapped support
607 CONFIG_CMD_MII * MII utility commands
608 CONFIG_CMD_NAND * NAND support
609 CONFIG_CMD_NET bootp, tftpboot, rarpboot
610 CONFIG_CMD_PCI * pciinfo
611 CONFIG_CMD_PCMCIA * PCMCIA support
612 CONFIG_CMD_PING * send ICMP ECHO_REQUEST to network
614 CONFIG_CMD_PORTIO * Port I/O
615 CONFIG_CMD_REGINFO * Register dump
616 CONFIG_CMD_RUN run command in env variable
617 CONFIG_CMD_SAVES * save S record dump
618 CONFIG_CMD_SCSI * SCSI Support
619 CONFIG_CMD_SDRAM * print SDRAM configuration information
620 (requires CONFIG_CMD_I2C)
621 CONFIG_CMD_SETGETDCR Support for DCR Register access
623 CONFIG_CMD_SPI * SPI serial bus support
624 CONFIG_CMD_USB * USB support
625 CONFIG_CMD_VFD * VFD support (TRAB)
626 CONFIG_CMD_BSP * Board SPecific functions
627 CONFIG_CMD_CDP * Cisco Discover Protocol support
628 CONFIG_CMD_FSL * Microblaze FSL support
631 EXAMPLE: If you want all functions except of network
632 support you can write:
634 #include "config_cmd_all.h"
635 #undef CONFIG_CMD_NET
638 fdt (flattened device tree) command: CONFIG_OF_LIBFDT
640 Note: Don't enable the "icache" and "dcache" commands
641 (configuration option CONFIG_CMD_CACHE) unless you know
642 what you (and your U-Boot users) are doing. Data
643 cache cannot be enabled on systems like the 8xx or
644 8260 (where accesses to the IMMR region must be
645 uncached), and it cannot be disabled on all other
646 systems where we (mis-) use the data cache to hold an
647 initial stack and some data.
650 XXX - this list needs to get updated!
654 If this variable is defined, it enables watchdog
655 support. There must be support in the platform specific
656 code for a watchdog. For the 8xx and 8260 CPUs, the
657 SIU Watchdog feature is enabled in the SYPCR
661 CONFIG_VERSION_VARIABLE
662 If this variable is defined, an environment variable
663 named "ver" is created by U-Boot showing the U-Boot
664 version as printed by the "version" command.
665 This variable is readonly.
669 When CONFIG_CMD_DATE is selected, the type of the RTC
670 has to be selected, too. Define exactly one of the
673 CONFIG_RTC_MPC8xx - use internal RTC of MPC8xx
674 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC
675 CONFIG_RTC_MC146818 - use MC146818 RTC
676 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC
677 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC
678 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC
679 CONFIG_RTC_DS164x - use Dallas DS164x RTC
680 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC
681 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC
682 CFG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337
684 Note that if the RTC uses I2C, then the I2C interface
685 must also be configured. See I2C Support, below.
689 When CONFIG_TIMESTAMP is selected, the timestamp
690 (date and time) of an image is printed by image
691 commands like bootm or iminfo. This option is
692 automatically enabled when you select CONFIG_CMD_DATE .
695 CONFIG_MAC_PARTITION and/or CONFIG_DOS_PARTITION
696 and/or CONFIG_ISO_PARTITION
698 If IDE or SCSI support is enabled (CONFIG_CMD_IDE or
699 CONFIG_CMD_SCSI) you must configure support for at
700 least one partition type as well.
703 CONFIG_IDE_RESET_ROUTINE - this is defined in several
704 board configurations files but used nowhere!
706 CONFIG_IDE_RESET - is this is defined, IDE Reset will
707 be performed by calling the function
708 ide_set_reset(int reset)
709 which has to be defined in a board specific file
714 Set this to enable ATAPI support.
719 Set this to enable support for disks larger than 137GB
720 Also look at CFG_64BIT_LBA ,CFG_64BIT_VSPRINTF and CFG_64BIT_STRTOUL
721 Whithout these , LBA48 support uses 32bit variables and will 'only'
722 support disks up to 2.1TB.
725 When enabled, makes the IDE subsystem use 64bit sector addresses.
729 At the moment only there is only support for the
730 SYM53C8XX SCSI controller; define
731 CONFIG_SCSI_SYM53C8XX to enable it.
733 CFG_SCSI_MAX_LUN [8], CFG_SCSI_MAX_SCSI_ID [7] and
734 CFG_SCSI_MAX_DEVICE [CFG_SCSI_MAX_SCSI_ID *
735 CFG_SCSI_MAX_LUN] can be adjusted to define the
736 maximum numbers of LUNs, SCSI ID's and target
738 CFG_SCSI_SYM53C8XX_CCF to fix clock timing (80Mhz)
740 - NETWORK Support (PCI):
742 Support for Intel 8254x gigabit chips.
744 CONFIG_E1000_FALLBACK_MAC
745 default MAC for empty eeprom after production.
748 Support for Intel 82557/82559/82559ER chips.
749 Optional CONFIG_EEPRO100_SROM_WRITE enables eeprom
750 write routine for first time initialisation.
753 Support for Digital 2114x chips.
754 Optional CONFIG_TULIP_SELECT_MEDIA for board specific
755 modem chip initialisation (KS8761/QS6611).
758 Support for National dp83815 chips.
761 Support for National dp8382[01] gigabit chips.
763 - NETWORK Support (other):
765 CONFIG_DRIVER_LAN91C96
766 Support for SMSC's LAN91C96 chips.
769 Define this to hold the physical address
770 of the LAN91C96's I/O space
772 CONFIG_LAN91C96_USE_32_BIT
773 Define this to enable 32 bit addressing
775 CONFIG_DRIVER_SMC91111
776 Support for SMSC's LAN91C111 chip
779 Define this to hold the physical address
780 of the device (I/O space)
782 CONFIG_SMC_USE_32_BIT
783 Define this if data bus is 32 bits
785 CONFIG_SMC_USE_IOFUNCS
786 Define this to use i/o functions instead of macros
787 (some hardware wont work with macros)
790 At the moment only the UHCI host controller is
791 supported (PIP405, MIP405, MPC5200); define
792 CONFIG_USB_UHCI to enable it.
793 define CONFIG_USB_KEYBOARD to enable the USB Keyboard
794 and define CONFIG_USB_STORAGE to enable the USB
797 Supported are USB Keyboards and USB Floppy drives
799 MPC5200 USB requires additional defines:
801 for 528 MHz Clock: 0x0001bbbb
803 for differential drivers: 0x00001000
804 for single ended drivers: 0x00005000
806 May be defined to allow interrupt polling
807 instead of using asynchronous interrupts
810 Define the below if you wish to use the USB console.
811 Once firmware is rebuilt from a serial console issue the
812 command "setenv stdin usbtty; setenv stdout usbtty" and
813 attach your usb cable. The Unix command "dmesg" should print
814 it has found a new device. The environment variable usbtty
815 can be set to gserial or cdc_acm to enable your device to
816 appear to a USB host as a Linux gserial device or a
817 Common Device Class Abstract Control Model serial device.
818 If you select usbtty = gserial you should be able to enumerate
820 # modprobe usbserial vendor=0xVendorID product=0xProductID
821 else if using cdc_acm, simply setting the environment
822 variable usbtty to be cdc_acm should suffice. The following
823 might be defined in YourBoardName.h
826 Define this to build a UDC device
829 Define this to have a tty type of device available to
830 talk to the UDC device
832 CFG_CONSOLE_IS_IN_ENV
833 Define this if you want stdin, stdout &/or stderr to
837 CFG_USB_EXTC_CLK 0xBLAH
838 Derive USB clock from external clock "blah"
839 - CFG_USB_EXTC_CLK 0x02
841 CFG_USB_BRG_CLK 0xBLAH
842 Derive USB clock from brgclk
843 - CFG_USB_BRG_CLK 0x04
845 If you have a USB-IF assigned VendorID then you may wish to
846 define your own vendor specific values either in BoardName.h
847 or directly in usbd_vendor_info.h. If you don't define
848 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME,
849 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot
850 should pretend to be a Linux device to it's target host.
852 CONFIG_USBD_MANUFACTURER
853 Define this string as the name of your company for
854 - CONFIG_USBD_MANUFACTURER "my company"
856 CONFIG_USBD_PRODUCT_NAME
857 Define this string as the name of your product
858 - CONFIG_USBD_PRODUCT_NAME "acme usb device"
861 Define this as your assigned Vendor ID from the USB
862 Implementors Forum. This *must* be a genuine Vendor ID
863 to avoid polluting the USB namespace.
864 - CONFIG_USBD_VENDORID 0xFFFF
866 CONFIG_USBD_PRODUCTID
867 Define this as the unique Product ID
869 - CONFIG_USBD_PRODUCTID 0xFFFF
873 The MMC controller on the Intel PXA is supported. To
874 enable this define CONFIG_MMC. The MMC can be
875 accessed from the boot prompt by mapping the device
876 to physical memory similar to flash. Command line is
877 enabled with CONFIG_CMD_MMC. The MMC driver also works with
878 the FAT fs. This is enabled with CONFIG_CMD_FAT.
880 - Journaling Flash filesystem support:
881 CONFIG_JFFS2_NAND, CONFIG_JFFS2_NAND_OFF, CONFIG_JFFS2_NAND_SIZE,
882 CONFIG_JFFS2_NAND_DEV
883 Define these for a default partition on a NAND device
885 CFG_JFFS2_FIRST_SECTOR,
886 CFG_JFFS2_FIRST_BANK, CFG_JFFS2_NUM_BANKS
887 Define these for a default partition on a NOR device
890 Define this to create an own partition. You have to provide a
891 function struct part_info* jffs2_part_info(int part_num)
893 If you define only one JFFS2 partition you may also want to
894 #define CFG_JFFS_SINGLE_PART 1
895 to disable the command chpart. This is the default when you
896 have not defined a custom partition
901 Define this to enable standard (PC-Style) keyboard
905 Standard PC keyboard driver with US (is default) and
906 GERMAN key layout (switch via environment 'keymap=de') support.
907 Export function i8042_kbd_init, i8042_tstc and i8042_getc
908 for cfb_console. Supports cursor blinking.
913 Define this to enable video support (for output to
918 Enable Chips & Technologies 69000 Video chip
920 CONFIG_VIDEO_SMI_LYNXEM
921 Enable Silicon Motion SMI 712/710/810 Video chip. The
922 video output is selected via environment 'videoout'
923 (1 = LCD and 2 = CRT). If videoout is undefined, CRT is
926 For the CT69000 and SMI_LYNXEM drivers, videomode is
927 selected via environment 'videomode'. Two diferent ways
929 - "videomode=num" 'num' is a standard LiLo mode numbers.
930 Following standard modes are supported (* is default):
932 Colors 640x480 800x600 1024x768 1152x864 1280x1024
933 -------------+---------------------------------------------
934 8 bits | 0x301* 0x303 0x305 0x161 0x307
935 15 bits | 0x310 0x313 0x316 0x162 0x319
936 16 bits | 0x311 0x314 0x317 0x163 0x31A
937 24 bits | 0x312 0x315 0x318 ? 0x31B
938 -------------+---------------------------------------------
939 (i.e. setenv videomode 317; saveenv; reset;)
941 - "videomode=bootargs" all the video parameters are parsed
942 from the bootargs. (See drivers/video/videomodes.c)
945 CONFIG_VIDEO_SED13806
946 Enable Epson SED13806 driver. This driver supports 8bpp
947 and 16bpp modes defined by CONFIG_VIDEO_SED13806_8BPP
948 or CONFIG_VIDEO_SED13806_16BPP
953 Define this to enable a custom keyboard support.
954 This simply calls drv_keyboard_init() which must be
955 defined in your board-specific files.
956 The only board using this so far is RBC823.
958 - LCD Support: CONFIG_LCD
960 Define this to enable LCD support (for output to LCD
961 display); also select one of the supported displays
962 by defining one of these:
964 CONFIG_NEC_NL6448AC33:
966 NEC NL6448AC33-18. Active, color, single scan.
968 CONFIG_NEC_NL6448BC20
970 NEC NL6448BC20-08. 6.5", 640x480.
971 Active, color, single scan.
973 CONFIG_NEC_NL6448BC33_54
975 NEC NL6448BC33-54. 10.4", 640x480.
976 Active, color, single scan.
980 Sharp 320x240. Active, color, single scan.
981 It isn't 16x9, and I am not sure what it is.
983 CONFIG_SHARP_LQ64D341
985 Sharp LQ64D341 display, 640x480.
986 Active, color, single scan.
990 HLD1045 display, 640x480.
991 Active, color, single scan.
995 Optrex CBL50840-2 NF-FW 99 22 M5
997 Hitachi LMG6912RPFC-00T
1001 320x240. Black & white.
1003 Normally display is black on white background; define
1004 CFG_WHITE_ON_BLACK to get it inverted.
1006 - Splash Screen Support: CONFIG_SPLASH_SCREEN
1008 If this option is set, the environment is checked for
1009 a variable "splashimage". If found, the usual display
1010 of logo, copyright and system information on the LCD
1011 is suppressed and the BMP image at the address
1012 specified in "splashimage" is loaded instead. The
1013 console is redirected to the "nulldev", too. This
1014 allows for a "silent" boot where a splash screen is
1015 loaded very quickly after power-on.
1017 - Gzip compressed BMP image support: CONFIG_VIDEO_BMP_GZIP
1019 If this option is set, additionally to standard BMP
1020 images, gzipped BMP images can be displayed via the
1021 splashscreen support or the bmp command.
1023 - Compression support:
1026 If this option is set, support for bzip2 compressed
1027 images is included. If not, only uncompressed and gzip
1028 compressed images are supported.
1030 NOTE: the bzip2 algorithm requires a lot of RAM, so
1031 the malloc area (as defined by CFG_MALLOC_LEN) should
1037 The address of PHY on MII bus.
1039 CONFIG_PHY_CLOCK_FREQ (ppc4xx)
1041 The clock frequency of the MII bus
1045 If this option is set, support for speed/duplex
1046 detection of Gigabit PHY is included.
1048 CONFIG_PHY_RESET_DELAY
1050 Some PHY like Intel LXT971A need extra delay after
1051 reset before any MII register access is possible.
1052 For such PHY, set this option to the usec delay
1053 required. (minimum 300usec for LXT971A)
1055 CONFIG_PHY_CMD_DELAY (ppc4xx)
1057 Some PHY like Intel LXT971A need extra delay after
1058 command issued before MII status register can be read
1065 Define a default value for ethernet address to use
1066 for the respective ethernet interface, in case this
1067 is not determined automatically.
1072 Define a default value for the IP address to use for
1073 the default ethernet interface, in case this is not
1074 determined through e.g. bootp.
1076 - Server IP address:
1079 Defines a default value for theIP address of a TFTP
1080 server to contact when using the "tftboot" command.
1082 - Multicast TFTP Mode:
1085 Defines whether you want to support multicast TFTP as per
1086 rfc-2090; for example to work with atftp. Lets lots of targets
1087 tftp down the same boot image concurrently. Note: the ethernet
1088 driver in use must provide a function: mcast() to join/leave a
1091 CONFIG_BOOTP_RANDOM_DELAY
1092 - BOOTP Recovery Mode:
1093 CONFIG_BOOTP_RANDOM_DELAY
1095 If you have many targets in a network that try to
1096 boot using BOOTP, you may want to avoid that all
1097 systems send out BOOTP requests at precisely the same
1098 moment (which would happen for instance at recovery
1099 from a power failure, when all systems will try to
1100 boot, thus flooding the BOOTP server. Defining
1101 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be
1102 inserted before sending out BOOTP requests. The
1103 following delays are inserted then:
1105 1st BOOTP request: delay 0 ... 1 sec
1106 2nd BOOTP request: delay 0 ... 2 sec
1107 3rd BOOTP request: delay 0 ... 4 sec
1109 BOOTP requests: delay 0 ... 8 sec
1111 - DHCP Advanced Options:
1112 You can fine tune the DHCP functionality by defining
1113 CONFIG_BOOTP_* symbols:
1115 CONFIG_BOOTP_SUBNETMASK
1116 CONFIG_BOOTP_GATEWAY
1117 CONFIG_BOOTP_HOSTNAME
1118 CONFIG_BOOTP_NISDOMAIN
1119 CONFIG_BOOTP_BOOTPATH
1120 CONFIG_BOOTP_BOOTFILESIZE
1123 CONFIG_BOOTP_SEND_HOSTNAME
1124 CONFIG_BOOTP_NTPSERVER
1125 CONFIG_BOOTP_TIMEOFFSET
1126 CONFIG_BOOTP_VENDOREX
1128 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
1129 environment variable, not the BOOTP server.
1131 CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
1132 serverip from a DHCP server, it is possible that more
1133 than one DNS serverip is offered to the client.
1134 If CONFIG_BOOTP_DNS2 is enabled, the secondary DNS
1135 serverip will be stored in the additional environment
1136 variable "dnsip2". The first DNS serverip is always
1137 stored in the variable "dnsip", when CONFIG_BOOTP_DNS
1140 CONFIG_BOOTP_SEND_HOSTNAME - Some DHCP servers are capable
1141 to do a dynamic update of a DNS server. To do this, they
1142 need the hostname of the DHCP requester.
1143 If CONFIG_BOOTP_SEND_HOSTNAME is defined, the content
1144 of the "hostname" environment variable is passed as
1145 option 12 to the DHCP server.
1147 CONFIG_BOOTP_DHCP_REQUEST_DELAY
1149 A 32bit value in microseconds for a delay between
1150 receiving a "DHCP Offer" and sending the "DHCP Request".
1151 This fixes a problem with certain DHCP servers that don't
1152 respond 100% of the time to a "DHCP request". E.g. On an
1153 AT91RM9200 processor running at 180MHz, this delay needed
1154 to be *at least* 15,000 usec before a Windows Server 2003
1155 DHCP server would reply 100% of the time. I recommend at
1156 least 50,000 usec to be safe. The alternative is to hope
1157 that one of the retries will be successful but note that
1158 the DHCP timeout and retry process takes a longer than
1162 CONFIG_CDP_DEVICE_ID
1164 The device id used in CDP trigger frames.
1166 CONFIG_CDP_DEVICE_ID_PREFIX
1168 A two character string which is prefixed to the MAC address
1173 A printf format string which contains the ascii name of
1174 the port. Normally is set to "eth%d" which sets
1175 eth0 for the first ethernet, eth1 for the second etc.
1177 CONFIG_CDP_CAPABILITIES
1179 A 32bit integer which indicates the device capabilities;
1180 0x00000010 for a normal host which does not forwards.
1184 An ascii string containing the version of the software.
1188 An ascii string containing the name of the platform.
1192 A 32bit integer sent on the trigger.
1194 CONFIG_CDP_POWER_CONSUMPTION
1196 A 16bit integer containing the power consumption of the
1197 device in .1 of milliwatts.
1199 CONFIG_CDP_APPLIANCE_VLAN_TYPE
1201 A byte containing the id of the VLAN.
1203 - Status LED: CONFIG_STATUS_LED
1205 Several configurations allow to display the current
1206 status using a LED. For instance, the LED will blink
1207 fast while running U-Boot code, stop blinking as
1208 soon as a reply to a BOOTP request was received, and
1209 start blinking slow once the Linux kernel is running
1210 (supported by a status LED driver in the Linux
1211 kernel). Defining CONFIG_STATUS_LED enables this
1214 - CAN Support: CONFIG_CAN_DRIVER
1216 Defining CONFIG_CAN_DRIVER enables CAN driver support
1217 on those systems that support this (optional)
1218 feature, like the TQM8xxL modules.
1220 - I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
1222 These enable I2C serial bus commands. Defining either of
1223 (but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
1224 include the appropriate I2C driver for the selected cpu.
1226 This will allow you to use i2c commands at the u-boot
1227 command line (as long as you set CONFIG_CMD_I2C in
1228 CONFIG_COMMANDS) and communicate with i2c based realtime
1229 clock chips. See common/cmd_i2c.c for a description of the
1230 command line interface.
1232 CONFIG_I2C_CMD_TREE is a recommended option that places
1233 all I2C commands under a single 'i2c' root command. The
1234 older 'imm', 'imd', 'iprobe' etc. commands are considered
1235 deprecated and may disappear in the future.
1237 CONFIG_HARD_I2C selects a hardware I2C controller.
1239 CONFIG_SOFT_I2C configures u-boot to use a software (aka
1240 bit-banging) driver instead of CPM or similar hardware
1243 There are several other quantities that must also be
1244 defined when you define CONFIG_HARD_I2C or CONFIG_SOFT_I2C.
1246 In both cases you will need to define CFG_I2C_SPEED
1247 to be the frequency (in Hz) at which you wish your i2c bus
1248 to run and CFG_I2C_SLAVE to be the address of this node (ie
1249 the cpu's i2c node address).
1251 Now, the u-boot i2c code for the mpc8xx (cpu/mpc8xx/i2c.c)
1252 sets the cpu up as a master node and so its address should
1253 therefore be cleared to 0 (See, eg, MPC823e User's Manual
1254 p.16-473). So, set CFG_I2C_SLAVE to 0.
1256 That's all that's required for CONFIG_HARD_I2C.
1258 If you use the software i2c interface (CONFIG_SOFT_I2C)
1259 then the following macros need to be defined (examples are
1260 from include/configs/lwmon.h):
1264 (Optional). Any commands necessary to enable the I2C
1265 controller or configure ports.
1267 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL)
1271 (Only for MPC8260 CPU). The I/O port to use (the code
1272 assumes both bits are on the same port). Valid values
1273 are 0..3 for ports A..D.
1277 The code necessary to make the I2C data line active
1278 (driven). If the data line is open collector, this
1281 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA)
1285 The code necessary to make the I2C data line tri-stated
1286 (inactive). If the data line is open collector, this
1289 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA)
1293 Code that returns TRUE if the I2C data line is high,
1296 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0)
1300 If <bit> is TRUE, sets the I2C data line high. If it
1301 is FALSE, it clears it (low).
1303 eg: #define I2C_SDA(bit) \
1304 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \
1305 else immr->im_cpm.cp_pbdat &= ~PB_SDA
1309 If <bit> is TRUE, sets the I2C clock line high. If it
1310 is FALSE, it clears it (low).
1312 eg: #define I2C_SCL(bit) \
1313 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \
1314 else immr->im_cpm.cp_pbdat &= ~PB_SCL
1318 This delay is invoked four times per clock cycle so this
1319 controls the rate of data transfer. The data rate thus
1320 is 1 / (I2C_DELAY * 4). Often defined to be something
1323 #define I2C_DELAY udelay(2)
1327 When a board is reset during an i2c bus transfer
1328 chips might think that the current transfer is still
1329 in progress. On some boards it is possible to access
1330 the i2c SCLK line directly, either by using the
1331 processor pin as a GPIO or by having a second pin
1332 connected to the bus. If this option is defined a
1333 custom i2c_init_board() routine in boards/xxx/board.c
1334 is run early in the boot sequence.
1336 CONFIG_I2CFAST (PPC405GP|PPC405EP only)
1338 This option enables configuration of bi_iic_fast[] flags
1339 in u-boot bd_info structure based on u-boot environment
1340 variable "i2cfast". (see also i2cfast)
1342 CONFIG_I2C_MULTI_BUS
1344 This option allows the use of multiple I2C buses, each of which
1345 must have a controller. At any point in time, only one bus is
1346 active. To switch to a different bus, use the 'i2c dev' command.
1347 Note that bus numbering is zero-based.
1351 This option specifies a list of I2C devices that will be skipped
1352 when the 'i2c probe' command is issued (or 'iprobe' using the legacy
1353 command). If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
1354 pairs. Otherwise, specify a 1D array of device addresses
1357 #undef CONFIG_I2C_MULTI_BUS
1358 #define CFG_I2C_NOPROBES {0x50,0x68}
1360 will skip addresses 0x50 and 0x68 on a board with one I2C bus
1362 #define CONFIG_I2C_MULTI_BUS
1363 #define CFG_I2C_MULTI_NOPROBES {{0,0x50},{0,0x68},{1,0x54}}
1365 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
1369 If defined, then this indicates the I2C bus number for DDR SPD.
1370 If not defined, then U-Boot assumes that SPD is on I2C bus 0.
1374 If defined, then this indicates the I2C bus number for the RTC.
1375 If not defined, then U-Boot assumes that RTC is on I2C bus 0.
1379 If defined, then this indicates the I2C bus number for the DTT.
1380 If not defined, then U-Boot assumes that DTT is on I2C bus 0.
1384 Define this option if you want to use Freescale's I2C driver in
1385 drivers/i2c/fsl_i2c.c.
1388 - SPI Support: CONFIG_SPI
1390 Enables SPI driver (so far only tested with
1391 SPI EEPROM, also an instance works with Crystal A/D and
1392 D/As on the SACSng board)
1396 Enables extended (16-bit) SPI EEPROM addressing.
1397 (symmetrical to CONFIG_I2C_X)
1401 Enables a software (bit-bang) SPI driver rather than
1402 using hardware support. This is a general purpose
1403 driver that only requires three general I/O port pins
1404 (two outputs, one input) to function. If this is
1405 defined, the board configuration must define several
1406 SPI configuration items (port pins to use, etc). For
1407 an example, see include/configs/sacsng.h.
1411 Enables a hardware SPI driver for general-purpose reads
1412 and writes. As with CONFIG_SOFT_SPI, the board configuration
1413 must define a list of chip-select function pointers.
1414 Currently supported on some MPC8xxx processors. For an
1415 example, see include/configs/mpc8349emds.h.
1419 Enables the driver for the SPI controllers on i.MX and MXC
1420 SoCs. Currently only i.MX31 is supported.
1422 - FPGA Support: CONFIG_FPGA
1424 Enables FPGA subsystem.
1426 CONFIG_FPGA_<vendor>
1428 Enables support for specific chip vendors.
1431 CONFIG_FPGA_<family>
1433 Enables support for FPGA family.
1434 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX)
1438 Specify the number of FPGA devices to support.
1440 CFG_FPGA_PROG_FEEDBACK
1442 Enable printing of hash marks during FPGA configuration.
1446 Enable checks on FPGA configuration interface busy
1447 status by the configuration function. This option
1448 will require a board or device specific function to
1453 If defined, a function that provides delays in the FPGA
1454 configuration driver.
1456 CFG_FPGA_CHECK_CTRLC
1457 Allow Control-C to interrupt FPGA configuration
1459 CFG_FPGA_CHECK_ERROR
1461 Check for configuration errors during FPGA bitfile
1462 loading. For example, abort during Virtex II
1463 configuration if the INIT_B line goes low (which
1464 indicated a CRC error).
1468 Maximum time to wait for the INIT_B line to deassert
1469 after PROB_B has been deasserted during a Virtex II
1470 FPGA configuration sequence. The default time is 500
1475 Maximum time to wait for BUSY to deassert during
1476 Virtex II FPGA configuration. The default is 5 mS.
1478 CFG_FPGA_WAIT_CONFIG
1480 Time to wait after FPGA configuration. The default is
1483 - Configuration Management:
1486 If defined, this string will be added to the U-Boot
1487 version information (U_BOOT_VERSION)
1489 - Vendor Parameter Protection:
1491 U-Boot considers the values of the environment
1492 variables "serial#" (Board Serial Number) and
1493 "ethaddr" (Ethernet Address) to be parameters that
1494 are set once by the board vendor / manufacturer, and
1495 protects these variables from casual modification by
1496 the user. Once set, these variables are read-only,
1497 and write or delete attempts are rejected. You can
1498 change this behviour:
1500 If CONFIG_ENV_OVERWRITE is #defined in your config
1501 file, the write protection for vendor parameters is
1502 completely disabled. Anybody can change or delete
1505 Alternatively, if you #define _both_ CONFIG_ETHADDR
1506 _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default
1507 ethernet address is installed in the environment,
1508 which can be changed exactly ONCE by the user. [The
1509 serial# is unaffected by this, i. e. it remains
1515 Define this variable to enable the reservation of
1516 "protected RAM", i. e. RAM which is not overwritten
1517 by U-Boot. Define CONFIG_PRAM to hold the number of
1518 kB you want to reserve for pRAM. You can overwrite
1519 this default value by defining an environment
1520 variable "pram" to the number of kB you want to
1521 reserve. Note that the board info structure will
1522 still show the full amount of RAM. If pRAM is
1523 reserved, a new environment variable "mem" will
1524 automatically be defined to hold the amount of
1525 remaining RAM in a form that can be passed as boot
1526 argument to Linux, for instance like that:
1528 setenv bootargs ... mem=\${mem}
1531 This way you can tell Linux not to use this memory,
1532 either, which results in a memory region that will
1533 not be affected by reboots.
1535 *WARNING* If your board configuration uses automatic
1536 detection of the RAM size, you must make sure that
1537 this memory test is non-destructive. So far, the
1538 following board configurations are known to be
1541 ETX094, IVMS8, IVML24, SPD8xx, TQM8xxL,
1542 HERMES, IP860, RPXlite, LWMON, LANTEC,
1543 PCU_E, FLAGADM, TQM8260
1548 Define this variable to stop the system in case of a
1549 fatal error, so that you have to reset it manually.
1550 This is probably NOT a good idea for an embedded
1551 system where you want to system to reboot
1552 automatically as fast as possible, but it may be
1553 useful during development since you can try to debug
1554 the conditions that lead to the situation.
1556 CONFIG_NET_RETRY_COUNT
1558 This variable defines the number of retries for
1559 network operations like ARP, RARP, TFTP, or BOOTP
1560 before giving up the operation. If not defined, a
1561 default value of 5 is used.
1563 - Command Interpreter:
1564 CONFIG_AUTO_COMPLETE
1566 Enable auto completion of commands using TAB.
1568 Note that this feature has NOT been implemented yet
1569 for the "hush" shell.
1574 Define this variable to enable the "hush" shell (from
1575 Busybox) as command line interpreter, thus enabling
1576 powerful command line syntax like
1577 if...then...else...fi conditionals or `&&' and '||'
1578 constructs ("shell scripts").
1580 If undefined, you get the old, much simpler behaviour
1581 with a somewhat smaller memory footprint.
1586 This defines the secondary prompt string, which is
1587 printed when the command interpreter needs more input
1588 to complete a command. Usually "> ".
1592 In the current implementation, the local variables
1593 space and global environment variables space are
1594 separated. Local variables are those you define by
1595 simply typing `name=value'. To access a local
1596 variable later on, you have write `$name' or
1597 `${name}'; to execute the contents of a variable
1598 directly type `$name' at the command prompt.
1600 Global environment variables are those you use
1601 setenv/printenv to work with. To run a command stored
1602 in such a variable, you need to use the run command,
1603 and you must not use the '$' sign to access them.
1605 To store commands and special characters in a
1606 variable, please use double quotation marks
1607 surrounding the whole text of the variable, instead
1608 of the backslashes before semicolons and special
1611 - Commandline Editing and History:
1612 CONFIG_CMDLINE_EDITING
1614 Enable editiong and History functions for interactive
1615 commandline input operations
1617 - Default Environment:
1618 CONFIG_EXTRA_ENV_SETTINGS
1620 Define this to contain any number of null terminated
1621 strings (variable = value pairs) that will be part of
1622 the default environment compiled into the boot image.
1624 For example, place something like this in your
1625 board's config file:
1627 #define CONFIG_EXTRA_ENV_SETTINGS \
1631 Warning: This method is based on knowledge about the
1632 internal format how the environment is stored by the
1633 U-Boot code. This is NOT an official, exported
1634 interface! Although it is unlikely that this format
1635 will change soon, there is no guarantee either.
1636 You better know what you are doing here.
1638 Note: overly (ab)use of the default environment is
1639 discouraged. Make sure to check other ways to preset
1640 the environment like the autoscript function or the
1643 - DataFlash Support:
1644 CONFIG_HAS_DATAFLASH
1646 Defining this option enables DataFlash features and
1647 allows to read/write in Dataflash via the standard
1650 - SystemACE Support:
1653 Adding this option adds support for Xilinx SystemACE
1654 chips attached via some sort of local bus. The address
1655 of the chip must alsh be defined in the
1656 CFG_SYSTEMACE_BASE macro. For example:
1658 #define CONFIG_SYSTEMACE
1659 #define CFG_SYSTEMACE_BASE 0xf0000000
1661 When SystemACE support is added, the "ace" device type
1662 becomes available to the fat commands, i.e. fatls.
1664 - TFTP Fixed UDP Port:
1667 If this is defined, the environment variable tftpsrcp
1668 is used to supply the TFTP UDP source port value.
1669 If tftpsrcp isn't defined, the normal pseudo-random port
1670 number generator is used.
1672 Also, the environment variable tftpdstp is used to supply
1673 the TFTP UDP destination port value. If tftpdstp isn't
1674 defined, the normal port 69 is used.
1676 The purpose for tftpsrcp is to allow a TFTP server to
1677 blindly start the TFTP transfer using the pre-configured
1678 target IP address and UDP port. This has the effect of
1679 "punching through" the (Windows XP) firewall, allowing
1680 the remainder of the TFTP transfer to proceed normally.
1681 A better solution is to properly configure the firewall,
1682 but sometimes that is not allowed.
1684 - Show boot progress:
1685 CONFIG_SHOW_BOOT_PROGRESS
1687 Defining this option allows to add some board-
1688 specific code (calling a user-provided function
1689 "show_boot_progress(int)") that enables you to show
1690 the system's boot progress on some display (for
1691 example, some LED's) on your board. At the moment,
1692 the following checkpoints are implemented:
1694 Legacy uImage format:
1697 1 common/cmd_bootm.c before attempting to boot an image
1698 -1 common/cmd_bootm.c Image header has bad magic number
1699 2 common/cmd_bootm.c Image header has correct magic number
1700 -2 common/cmd_bootm.c Image header has bad checksum
1701 3 common/cmd_bootm.c Image header has correct checksum
1702 -3 common/cmd_bootm.c Image data has bad checksum
1703 4 common/cmd_bootm.c Image data has correct checksum
1704 -4 common/cmd_bootm.c Image is for unsupported architecture
1705 5 common/cmd_bootm.c Architecture check OK
1706 -5 common/cmd_bootm.c Wrong Image Type (not kernel, multi)
1707 6 common/cmd_bootm.c Image Type check OK
1708 -6 common/cmd_bootm.c gunzip uncompression error
1709 -7 common/cmd_bootm.c Unimplemented compression type
1710 7 common/cmd_bootm.c Uncompression OK
1711 8 common/cmd_bootm.c No uncompress/copy overwrite error
1712 -9 common/cmd_bootm.c Unsupported OS (not Linux, BSD, VxWorks, QNX)
1714 9 common/image.c Start initial ramdisk verification
1715 -10 common/image.c Ramdisk header has bad magic number
1716 -11 common/image.c Ramdisk header has bad checksum
1717 10 common/image.c Ramdisk header is OK
1718 -12 common/image.c Ramdisk data has bad checksum
1719 11 common/image.c Ramdisk data has correct checksum
1720 12 common/image.c Ramdisk verification complete, start loading
1721 -13 common/image.c Wrong Image Type (not PPC Linux Ramdisk)
1722 13 common/image.c Start multifile image verification
1723 14 common/image.c No initial ramdisk, no multifile, continue.
1725 15 lib_<arch>/bootm.c All preparation done, transferring control to OS
1727 -30 lib_ppc/board.c Fatal error, hang the system
1728 -31 post/post.c POST test failed, detected by post_output_backlog()
1729 -32 post/post.c POST test failed, detected by post_run_single()
1731 34 common/cmd_doc.c before loading a Image from a DOC device
1732 -35 common/cmd_doc.c Bad usage of "doc" command
1733 35 common/cmd_doc.c correct usage of "doc" command
1734 -36 common/cmd_doc.c No boot device
1735 36 common/cmd_doc.c correct boot device
1736 -37 common/cmd_doc.c Unknown Chip ID on boot device
1737 37 common/cmd_doc.c correct chip ID found, device available
1738 -38 common/cmd_doc.c Read Error on boot device
1739 38 common/cmd_doc.c reading Image header from DOC device OK
1740 -39 common/cmd_doc.c Image header has bad magic number
1741 39 common/cmd_doc.c Image header has correct magic number
1742 -40 common/cmd_doc.c Error reading Image from DOC device
1743 40 common/cmd_doc.c Image header has correct magic number
1744 41 common/cmd_ide.c before loading a Image from a IDE device
1745 -42 common/cmd_ide.c Bad usage of "ide" command
1746 42 common/cmd_ide.c correct usage of "ide" command
1747 -43 common/cmd_ide.c No boot device
1748 43 common/cmd_ide.c boot device found
1749 -44 common/cmd_ide.c Device not available
1750 44 common/cmd_ide.c Device available
1751 -45 common/cmd_ide.c wrong partition selected
1752 45 common/cmd_ide.c partition selected
1753 -46 common/cmd_ide.c Unknown partition table
1754 46 common/cmd_ide.c valid partition table found
1755 -47 common/cmd_ide.c Invalid partition type
1756 47 common/cmd_ide.c correct partition type
1757 -48 common/cmd_ide.c Error reading Image Header on boot device
1758 48 common/cmd_ide.c reading Image Header from IDE device OK
1759 -49 common/cmd_ide.c Image header has bad magic number
1760 49 common/cmd_ide.c Image header has correct magic number
1761 -50 common/cmd_ide.c Image header has bad checksum
1762 50 common/cmd_ide.c Image header has correct checksum
1763 -51 common/cmd_ide.c Error reading Image from IDE device
1764 51 common/cmd_ide.c reading Image from IDE device OK
1765 52 common/cmd_nand.c before loading a Image from a NAND device
1766 -53 common/cmd_nand.c Bad usage of "nand" command
1767 53 common/cmd_nand.c correct usage of "nand" command
1768 -54 common/cmd_nand.c No boot device
1769 54 common/cmd_nand.c boot device found
1770 -55 common/cmd_nand.c Unknown Chip ID on boot device
1771 55 common/cmd_nand.c correct chip ID found, device available
1772 -56 common/cmd_nand.c Error reading Image Header on boot device
1773 56 common/cmd_nand.c reading Image Header from NAND device OK
1774 -57 common/cmd_nand.c Image header has bad magic number
1775 57 common/cmd_nand.c Image header has correct magic number
1776 -58 common/cmd_nand.c Error reading Image from NAND device
1777 58 common/cmd_nand.c reading Image from NAND device OK
1779 -60 common/env_common.c Environment has a bad CRC, using default
1781 64 net/eth.c starting with Ethernetconfiguration.
1782 -64 net/eth.c no Ethernet found.
1783 65 net/eth.c Ethernet found.
1785 -80 common/cmd_net.c usage wrong
1786 80 common/cmd_net.c before calling NetLoop()
1787 -81 common/cmd_net.c some error in NetLoop() occured
1788 81 common/cmd_net.c NetLoop() back without error
1789 -82 common/cmd_net.c size == 0 (File with size 0 loaded)
1790 82 common/cmd_net.c trying automatic boot
1791 83 common/cmd_net.c running autoscript
1792 -83 common/cmd_net.c some error in automatic boot or autoscript
1793 84 common/cmd_net.c end without errors
1798 100 common/cmd_bootm.c Kernel FIT Image has correct format
1799 -100 common/cmd_bootm.c Kernel FIT Image has incorrect format
1800 101 common/cmd_bootm.c No Kernel subimage unit name, using configuration
1801 -101 common/cmd_bootm.c Can't get configuration for kernel subimage
1802 102 common/cmd_bootm.c Kernel unit name specified
1803 -103 common/cmd_bootm.c Can't get kernel subimage node offset
1804 103 common/cmd_bootm.c Found configuration node
1805 104 common/cmd_bootm.c Got kernel subimage node offset
1806 -104 common/cmd_bootm.c Kernel subimage hash verification failed
1807 105 common/cmd_bootm.c Kernel subimage hash verification OK
1808 -105 common/cmd_bootm.c Kernel subimage is for unsupported architecture
1809 106 common/cmd_bootm.c Architecture check OK
1810 -106 common/cmd_bootm.c Kernel subimage has wrong typea
1811 107 common/cmd_bootm.c Kernel subimge type OK
1812 -107 common/cmd_bootm.c Can't get kernel subimage data/size
1813 108 common/cmd_bootm.c Got kernel subimage data/size
1814 -108 common/cmd_bootm.c Wrong image type (not legacy, FIT)
1815 -109 common/cmd_bootm.c Can't get kernel subimage type
1816 -110 common/cmd_bootm.c Can't get kernel subimage comp
1817 -111 common/cmd_bootm.c Can't get kernel subimage os
1818 -112 common/cmd_bootm.c Can't get kernel subimage load address
1819 -113 common/cmd_bootm.c Image uncompress/copy overwrite error
1821 120 common/image.c Start initial ramdisk verification
1822 -120 common/image.c Ramdisk FIT image has incorrect format
1823 121 common/image.c Ramdisk FIT image has correct format
1824 122 common/image.c No Ramdisk subimage unit name, using configuration
1825 -122 common/image.c Can't get configuration for ramdisk subimage
1826 123 common/image.c Ramdisk unit name specified
1827 -124 common/image.c Can't get ramdisk subimage node offset
1828 125 common/image.c Got ramdisk subimage node offset
1829 -125 common/image.c Ramdisk subimage hash verification failed
1830 126 common/image.c Ramdisk subimage hash verification OK
1831 -126 common/image.c Ramdisk subimage for unsupported architecture
1832 127 common/image.c Architecture check OK
1833 -127 common/image.c Can't get ramdisk subimage data/size
1834 128 common/image.c Got ramdisk subimage data/size
1835 129 common/image.c Can't get ramdisk load address
1836 -129 common/image.c Got ramdisk load address
1838 -130 common/cmd_doc.c Icorrect FIT image format
1839 131 common/cmd_doc.c FIT image format OK
1841 -140 common/cmd_ide.c Icorrect FIT image format
1842 141 common/cmd_ide.c FIT image format OK
1844 -150 common/cmd_nand.c Icorrect FIT image format
1845 151 common/cmd_nand.c FIT image format OK
1851 [so far only for SMDK2400 and TRAB boards]
1853 - Modem support endable:
1854 CONFIG_MODEM_SUPPORT
1856 - RTS/CTS Flow control enable:
1859 - Modem debug support:
1860 CONFIG_MODEM_SUPPORT_DEBUG
1862 Enables debugging stuff (char screen[1024], dbg())
1863 for modem support. Useful only with BDI2000.
1865 - Interrupt support (PPC):
1867 There are common interrupt_init() and timer_interrupt()
1868 for all PPC archs. interrupt_init() calls interrupt_init_cpu()
1869 for cpu specific initialization. interrupt_init_cpu()
1870 should set decrementer_count to appropriate value. If
1871 cpu resets decrementer automatically after interrupt
1872 (ppc4xx) it should set decrementer_count to zero.
1873 timer_interrupt() calls timer_interrupt_cpu() for cpu
1874 specific handling. If board has watchdog / status_led
1875 / other_activity_monitor it works automatically from
1876 general timer_interrupt().
1880 In the target system modem support is enabled when a
1881 specific key (key combination) is pressed during
1882 power-on. Otherwise U-Boot will boot normally
1883 (autoboot). The key_pressed() fuction is called from
1884 board_init(). Currently key_pressed() is a dummy
1885 function, returning 1 and thus enabling modem
1888 If there are no modem init strings in the
1889 environment, U-Boot proceed to autoboot; the
1890 previous output (banner, info printfs) will be
1893 See also: doc/README.Modem
1896 Configuration Settings:
1897 -----------------------
1899 - CFG_LONGHELP: Defined when you want long help messages included;
1900 undefine this when you're short of memory.
1902 - CFG_PROMPT: This is what U-Boot prints on the console to
1903 prompt for user input.
1905 - CFG_CBSIZE: Buffer size for input from the Console
1907 - CFG_PBSIZE: Buffer size for Console output
1909 - CFG_MAXARGS: max. Number of arguments accepted for monitor commands
1911 - CFG_BARGSIZE: Buffer size for Boot Arguments which are passed to
1912 the application (usually a Linux kernel) when it is
1915 - CFG_BAUDRATE_TABLE:
1916 List of legal baudrate settings for this board.
1918 - CFG_CONSOLE_INFO_QUIET
1919 Suppress display of console information at boot.
1921 - CFG_CONSOLE_IS_IN_ENV
1922 If the board specific function
1923 extern int overwrite_console (void);
1924 returns 1, the stdin, stderr and stdout are switched to the
1925 serial port, else the settings in the environment are used.
1927 - CFG_CONSOLE_OVERWRITE_ROUTINE
1928 Enable the call to overwrite_console().
1930 - CFG_CONSOLE_ENV_OVERWRITE
1931 Enable overwrite of previous console environment settings.
1933 - CFG_MEMTEST_START, CFG_MEMTEST_END:
1934 Begin and End addresses of the area used by the
1938 Enable an alternate, more extensive memory test.
1940 - CFG_MEMTEST_SCRATCH:
1941 Scratch address used by the alternate memory test
1942 You only need to set this if address zero isn't writeable
1944 - CFG_MEM_TOP_HIDE (PPC only):
1945 If CFG_MEM_TOP_HIDE is defined in the board config header,
1946 this specified memory area will get subtracted from the top
1947 (end) of ram and won't get "touched" at all by U-Boot. By
1948 fixing up gd->ram_size the Linux kernel should gets passed
1949 the now "corrected" memory size and won't touch it either.
1950 This should work for arch/ppc and arch/powerpc. Only Linux
1951 board ports in arch/powerpc with bootwrapper support that
1952 recalculate the memory size from the SDRAM controller setup
1953 will have to get fixed in Linux additionally.
1955 This option can be used as a workaround for the 440EPx/GRx
1956 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't
1959 WARNING: Please make sure that this value is a multiple of
1960 the Linux page size (normally 4k). If this is not the case,
1961 then the end address of the Linux memory will be located at a
1962 non page size aligned address and this could cause major
1965 - CFG_TFTP_LOADADDR:
1966 Default load address for network file downloads
1968 - CFG_LOADS_BAUD_CHANGE:
1969 Enable temporary baudrate change while serial download
1972 Physical start address of SDRAM. _Must_ be 0 here.
1975 Physical start address of Motherboard I/O (if using a
1979 Physical start address of Flash memory.
1982 Physical start address of boot monitor code (set by
1983 make config files to be same as the text base address
1984 (TEXT_BASE) used when linking) - same as
1985 CFG_FLASH_BASE when booting from flash.
1988 Size of memory reserved for monitor code, used to
1989 determine _at_compile_time_ (!) if the environment is
1990 embedded within the U-Boot image, or in a separate
1994 Size of DRAM reserved for malloc() use.
1997 Normally compressed uImages are limited to an
1998 uncompressed size of 8 MBytes. If this is not enough,
1999 you can define CFG_BOOTM_LEN in your board config file
2000 to adjust this setting to your needs.
2003 Maximum size of memory mapped by the startup code of
2004 the Linux kernel; all data that must be processed by
2005 the Linux kernel (bd_info, boot arguments, FDT blob if
2006 used) must be put below this limit, unless "bootm_low"
2007 enviroment variable is defined and non-zero. In such case
2008 all data for the Linux kernel must be between "bootm_low"
2009 and "bootm_low" + CFG_BOOTMAPSZ.
2011 - CFG_MAX_FLASH_BANKS:
2012 Max number of Flash memory banks
2014 - CFG_MAX_FLASH_SECT:
2015 Max number of sectors on a Flash chip
2017 - CFG_FLASH_ERASE_TOUT:
2018 Timeout for Flash erase operations (in ms)
2020 - CFG_FLASH_WRITE_TOUT:
2021 Timeout for Flash write operations (in ms)
2023 - CFG_FLASH_LOCK_TOUT
2024 Timeout for Flash set sector lock bit operation (in ms)
2026 - CFG_FLASH_UNLOCK_TOUT
2027 Timeout for Flash clear lock bits operation (in ms)
2029 - CFG_FLASH_PROTECTION
2030 If defined, hardware flash sectors protection is used
2031 instead of U-Boot software protection.
2033 - CFG_DIRECT_FLASH_TFTP:
2035 Enable TFTP transfers directly to flash memory;
2036 without this option such a download has to be
2037 performed in two steps: (1) download to RAM, and (2)
2038 copy from RAM to flash.
2040 The two-step approach is usually more reliable, since
2041 you can check if the download worked before you erase
2042 the flash, but in some situations (when sytem RAM is
2043 too limited to allow for a tempory copy of the
2044 downloaded image) this option may be very useful.
2047 Define if the flash driver uses extra elements in the
2048 common flash structure for storing flash geometry.
2050 - CFG_FLASH_CFI_DRIVER
2051 This option also enables the building of the cfi_flash driver
2052 in the drivers directory
2054 - CFG_FLASH_USE_BUFFER_WRITE
2055 Use buffered writes to flash.
2057 - CONFIG_FLASH_SPANSION_S29WS_N
2058 s29ws-n MirrorBit flash has non-standard addresses for buffered
2061 - CFG_FLASH_QUIET_TEST
2062 If this option is defined, the common CFI flash doesn't
2063 print it's warning upon not recognized FLASH banks. This
2064 is useful, if some of the configured banks are only
2065 optionally available.
2067 - CONFIG_FLASH_SHOW_PROGRESS
2068 If defined (must be an integer), print out countdown
2069 digits and dots. Recommended value: 45 (9..1) for 80
2070 column displays, 15 (3..1) for 40 column displays.
2072 - CFG_RX_ETH_BUFFER:
2073 Defines the number of ethernet receive buffers. On some
2074 ethernet controllers it is recommended to set this value
2075 to 8 or even higher (EEPRO100 or 405 EMAC), since all
2076 buffers can be full shortly after enabling the interface
2077 on high ethernet traffic.
2078 Defaults to 4 if not defined.
2080 The following definitions that deal with the placement and management
2081 of environment data (variable area); in general, we support the
2082 following configurations:
2084 - CFG_ENV_IS_IN_FLASH:
2086 Define this if the environment is in flash memory.
2088 a) The environment occupies one whole flash sector, which is
2089 "embedded" in the text segment with the U-Boot code. This
2090 happens usually with "bottom boot sector" or "top boot
2091 sector" type flash chips, which have several smaller
2092 sectors at the start or the end. For instance, such a
2093 layout can have sector sizes of 8, 2x4, 16, Nx32 kB. In
2094 such a case you would place the environment in one of the
2095 4 kB sectors - with U-Boot code before and after it. With
2096 "top boot sector" type flash chips, you would put the
2097 environment in one of the last sectors, leaving a gap
2098 between U-Boot and the environment.
2102 Offset of environment data (variable area) to the
2103 beginning of flash memory; for instance, with bottom boot
2104 type flash chips the second sector can be used: the offset
2105 for this sector is given here.
2107 CFG_ENV_OFFSET is used relative to CFG_FLASH_BASE.
2111 This is just another way to specify the start address of
2112 the flash sector containing the environment (instead of
2115 - CFG_ENV_SECT_SIZE:
2117 Size of the sector containing the environment.
2120 b) Sometimes flash chips have few, equal sized, BIG sectors.
2121 In such a case you don't want to spend a whole sector for
2126 If you use this in combination with CFG_ENV_IS_IN_FLASH
2127 and CFG_ENV_SECT_SIZE, you can specify to use only a part
2128 of this flash sector for the environment. This saves
2129 memory for the RAM copy of the environment.
2131 It may also save flash memory if you decide to use this
2132 when your environment is "embedded" within U-Boot code,
2133 since then the remainder of the flash sector could be used
2134 for U-Boot code. It should be pointed out that this is
2135 STRONGLY DISCOURAGED from a robustness point of view:
2136 updating the environment in flash makes it always
2137 necessary to erase the WHOLE sector. If something goes
2138 wrong before the contents has been restored from a copy in
2139 RAM, your target system will be dead.
2141 - CFG_ENV_ADDR_REDUND
2144 These settings describe a second storage area used to hold
2145 a redundand copy of the environment data, so that there is
2146 a valid backup copy in case there is a power failure during
2147 a "saveenv" operation.
2149 BE CAREFUL! Any changes to the flash layout, and some changes to the
2150 source code will make it necessary to adapt <board>/u-boot.lds*
2154 - CFG_ENV_IS_IN_NVRAM:
2156 Define this if you have some non-volatile memory device
2157 (NVRAM, battery buffered SRAM) which you want to use for the
2163 These two #defines are used to determin the memory area you
2164 want to use for environment. It is assumed that this memory
2165 can just be read and written to, without any special
2168 BE CAREFUL! The first access to the environment happens quite early
2169 in U-Boot initalization (when we try to get the setting of for the
2170 console baudrate). You *MUST* have mappend your NVRAM area then, or
2173 Please note that even with NVRAM we still use a copy of the
2174 environment in RAM: we could work on NVRAM directly, but we want to
2175 keep settings there always unmodified except somebody uses "saveenv"
2176 to save the current settings.
2179 - CFG_ENV_IS_IN_EEPROM:
2181 Use this if you have an EEPROM or similar serial access
2182 device and a driver for it.
2187 These two #defines specify the offset and size of the
2188 environment area within the total memory of your EEPROM.
2190 - CFG_I2C_EEPROM_ADDR:
2191 If defined, specified the chip address of the EEPROM device.
2192 The default address is zero.
2194 - CFG_EEPROM_PAGE_WRITE_BITS:
2195 If defined, the number of bits used to address bytes in a
2196 single page in the EEPROM device. A 64 byte page, for example
2197 would require six bits.
2199 - CFG_EEPROM_PAGE_WRITE_DELAY_MS:
2200 If defined, the number of milliseconds to delay between
2201 page writes. The default is zero milliseconds.
2203 - CFG_I2C_EEPROM_ADDR_LEN:
2204 The length in bytes of the EEPROM memory array address. Note
2205 that this is NOT the chip address length!
2207 - CFG_I2C_EEPROM_ADDR_OVERFLOW:
2208 EEPROM chips that implement "address overflow" are ones
2209 like Catalyst 24WC04/08/16 which has 9/10/11 bits of
2210 address and the extra bits end up in the "chip address" bit
2211 slots. This makes a 24WC08 (1Kbyte) chip look like four 256
2214 Note that we consider the length of the address field to
2215 still be one byte because the extra address bits are hidden
2216 in the chip address.
2219 The size in bytes of the EEPROM device.
2222 - CFG_ENV_IS_IN_DATAFLASH:
2224 Define this if you have a DataFlash memory device which you
2225 want to use for the environment.
2231 These three #defines specify the offset and size of the
2232 environment area within the total memory of your DataFlash placed
2233 at the specified address.
2235 - CFG_ENV_IS_IN_NAND:
2237 Define this if you have a NAND device which you want to use
2238 for the environment.
2243 These two #defines specify the offset and size of the environment
2244 area within the first NAND device.
2246 - CFG_ENV_OFFSET_REDUND
2248 This setting describes a second storage area of CFG_ENV_SIZE
2249 size used to hold a redundant copy of the environment data,
2250 so that there is a valid backup copy in case there is a
2251 power failure during a "saveenv" operation.
2253 Note: CFG_ENV_OFFSET and CFG_ENV_OFFSET_REDUND must be aligned
2254 to a block boundary, and CFG_ENV_SIZE must be a multiple of
2255 the NAND devices block size.
2257 - CFG_SPI_INIT_OFFSET
2259 Defines offset to the initial SPI buffer area in DPRAM. The
2260 area is used at an early stage (ROM part) if the environment
2261 is configured to reside in the SPI EEPROM: We need a 520 byte
2262 scratch DPRAM area. It is used between the two initialization
2263 calls (spi_init_f() and spi_init_r()). A value of 0xB00 seems
2264 to be a good choice since it makes it far enough from the
2265 start of the data area as well as from the stack pointer.
2267 Please note that the environment is read-only until the monitor
2268 has been relocated to RAM and a RAM copy of the environment has been
2269 created; also, when using EEPROM you will have to use getenv_r()
2270 until then to read environment variables.
2272 The environment is protected by a CRC32 checksum. Before the monitor
2273 is relocated into RAM, as a result of a bad CRC you will be working
2274 with the compiled-in default environment - *silently*!!! [This is
2275 necessary, because the first environment variable we need is the
2276 "baudrate" setting for the console - if we have a bad CRC, we don't
2277 have any device yet where we could complain.]
2279 Note: once the monitor has been relocated, then it will complain if
2280 the default environment is used; a new CRC is computed as soon as you
2281 use the "saveenv" command to store a valid environment.
2283 - CFG_FAULT_ECHO_LINK_DOWN:
2284 Echo the inverted Ethernet link state to the fault LED.
2286 Note: If this option is active, then CFG_FAULT_MII_ADDR
2287 also needs to be defined.
2289 - CFG_FAULT_MII_ADDR:
2290 MII address of the PHY to check for the Ethernet link state.
2292 - CFG_64BIT_VSPRINTF:
2293 Makes vsprintf (and all *printf functions) support printing
2294 of 64bit values by using the L quantifier
2296 - CFG_64BIT_STRTOUL:
2297 Adds simple_strtoull that returns a 64bit value
2299 Low Level (hardware related) configuration options:
2300 ---------------------------------------------------
2302 - CFG_CACHELINE_SIZE:
2303 Cache Line Size of the CPU.
2306 Default address of the IMMR after system reset.
2308 Needed on some 8260 systems (MPC8260ADS, PQ2FADS-ZU,
2309 and RPXsuper) to be able to adjust the position of
2310 the IMMR register after a reset.
2312 - Floppy Disk Support:
2313 CFG_FDC_DRIVE_NUMBER
2315 the default drive number (default value 0)
2319 defines the spacing between fdc chipset registers
2324 defines the offset of register from address. It
2325 depends on which part of the data bus is connected to
2326 the fdc chipset. (default value 0)
2328 If CFG_ISA_IO_STRIDE CFG_ISA_IO_OFFSET and
2329 CFG_FDC_DRIVE_NUMBER are undefined, they take their
2332 if CFG_FDC_HW_INIT is defined, then the function
2333 fdc_hw_init() is called at the beginning of the FDC
2334 setup. fdc_hw_init() must be provided by the board
2335 source code. It is used to make hardware dependant
2338 - CFG_IMMR: Physical address of the Internal Memory.
2339 DO NOT CHANGE unless you know exactly what you're
2340 doing! (11-4) [MPC8xx/82xx systems only]
2342 - CFG_INIT_RAM_ADDR:
2344 Start address of memory area that can be used for
2345 initial data and stack; please note that this must be
2346 writable memory that is working WITHOUT special
2347 initialization, i. e. you CANNOT use normal RAM which
2348 will become available only after programming the
2349 memory controller and running certain initialization
2352 U-Boot uses the following memory types:
2353 - MPC8xx and MPC8260: IMMR (internal memory of the CPU)
2354 - MPC824X: data cache
2355 - PPC4xx: data cache
2357 - CFG_GBL_DATA_OFFSET:
2359 Offset of the initial data structure in the memory
2360 area defined by CFG_INIT_RAM_ADDR. Usually
2361 CFG_GBL_DATA_OFFSET is chosen such that the initial
2362 data is located at the end of the available space
2363 (sometimes written as (CFG_INIT_RAM_END -
2364 CFG_INIT_DATA_SIZE), and the initial stack is just
2365 below that area (growing from (CFG_INIT_RAM_ADDR +
2366 CFG_GBL_DATA_OFFSET) downward.
2369 On the MPC824X (or other systems that use the data
2370 cache for initial memory) the address chosen for
2371 CFG_INIT_RAM_ADDR is basically arbitrary - it must
2372 point to an otherwise UNUSED address space between
2373 the top of RAM and the start of the PCI space.
2375 - CFG_SIUMCR: SIU Module Configuration (11-6)
2377 - CFG_SYPCR: System Protection Control (11-9)
2379 - CFG_TBSCR: Time Base Status and Control (11-26)
2381 - CFG_PISCR: Periodic Interrupt Status and Control (11-31)
2383 - CFG_PLPRCR: PLL, Low-Power, and Reset Control Register (15-30)
2385 - CFG_SCCR: System Clock and reset Control Register (15-27)
2387 - CFG_OR_TIMING_SDRAM:
2391 periodic timer for refresh
2393 - CFG_DER: Debug Event Register (37-47)
2395 - FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CFG_REMAP_OR_AM,
2396 CFG_PRELIM_OR_AM, CFG_OR_TIMING_FLASH, CFG_OR0_REMAP,
2397 CFG_OR0_PRELIM, CFG_BR0_PRELIM, CFG_OR1_REMAP, CFG_OR1_PRELIM,
2399 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH)
2401 - SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE,
2402 CFG_OR_TIMING_SDRAM, CFG_OR2_PRELIM, CFG_BR2_PRELIM,
2403 CFG_OR3_PRELIM, CFG_BR3_PRELIM:
2404 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM)
2406 - CFG_MAMR_PTA, CFG_MPTPR_2BK_4K, CFG_MPTPR_1BK_4K, CFG_MPTPR_2BK_8K,
2407 CFG_MPTPR_1BK_8K, CFG_MAMR_8COL, CFG_MAMR_9COL:
2408 Machine Mode Register and Memory Periodic Timer
2409 Prescaler definitions (SDRAM timing)
2411 - CFG_I2C_UCODE_PATCH, CFG_I2C_DPMEM_OFFSET [0x1FC0]:
2412 enable I2C microcode relocation patch (MPC8xx);
2413 define relocation offset in DPRAM [DSP2]
2415 - CFG_SMC_UCODE_PATCH, CFG_SMC_DPMEM_OFFSET [0x1FC0]:
2416 enable SMC microcode relocation patch (MPC8xx);
2417 define relocation offset in DPRAM [SMC1]
2419 - CFG_SPI_UCODE_PATCH, CFG_SPI_DPMEM_OFFSET [0x1FC0]:
2420 enable SPI microcode relocation patch (MPC8xx);
2421 define relocation offset in DPRAM [SCC4]
2424 Use OSCM clock mode on MBX8xx board. Be careful,
2425 wrong setting might damage your board. Read
2426 doc/README.MBX before setting this variable!
2428 - CFG_CPM_POST_WORD_ADDR: (MPC8xx, MPC8260 only)
2429 Offset of the bootmode word in DPRAM used by post
2430 (Power On Self Tests). This definition overrides
2431 #define'd default value in commproc.h resp.
2434 - CFG_PCI_SLV_MEM_LOCAL, CFG_PCI_SLV_MEM_BUS, CFG_PICMR0_MASK_ATTRIB,
2435 CFG_PCI_MSTR0_LOCAL, CFG_PCIMSK0_MASK, CFG_PCI_MSTR1_LOCAL,
2436 CFG_PCIMSK1_MASK, CFG_PCI_MSTR_MEM_LOCAL, CFG_PCI_MSTR_MEM_BUS,
2437 CFG_CPU_PCI_MEM_START, CFG_PCI_MSTR_MEM_SIZE, CFG_POCMR0_MASK_ATTRIB,
2438 CFG_PCI_MSTR_MEMIO_LOCAL, CFG_PCI_MSTR_MEMIO_BUS, CPU_PCI_MEMIO_START,
2439 CFG_PCI_MSTR_MEMIO_SIZE, CFG_POCMR1_MASK_ATTRIB, CFG_PCI_MSTR_IO_LOCAL,
2440 CFG_PCI_MSTR_IO_BUS, CFG_CPU_PCI_IO_START, CFG_PCI_MSTR_IO_SIZE,
2441 CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
2442 Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
2445 Get DDR timing information from an I2C EEPROM. Common
2446 with pluggable memory modules such as SODIMMs
2449 I2C address of the SPD EEPROM
2452 If SPD EEPROM is on an I2C bus other than the first
2453 one, specify here. Note that the value must resolve
2454 to something your driver can deal with.
2456 - CFG_83XX_DDR_USES_CS0
2457 Only for 83xx systems. If specified, then DDR should
2458 be configured using CS0 and CS1 instead of CS2 and CS3.
2460 - CFG_83XX_DDR_USES_CS0
2461 Only for 83xx systems. If specified, then DDR should
2462 be configured using CS0 and CS1 instead of CS2 and CS3.
2464 - CONFIG_ETHER_ON_FEC[12]
2465 Define to enable FEC[12] on a 8xx series processor.
2467 - CONFIG_FEC[12]_PHY
2468 Define to the hardcoded PHY address which corresponds
2469 to the given FEC; i. e.
2470 #define CONFIG_FEC1_PHY 4
2471 means that the PHY with address 4 is connected to FEC1
2473 When set to -1, means to probe for first available.
2475 - CONFIG_FEC[12]_PHY_NORXERR
2476 The PHY does not have a RXERR line (RMII only).
2477 (so program the FEC to ignore it).
2480 Enable RMII mode for all FECs.
2481 Note that this is a global option, we can't
2482 have one FEC in standard MII mode and another in RMII mode.
2484 - CONFIG_CRC32_VERIFY
2485 Add a verify option to the crc32 command.
2488 => crc32 -v <address> <count> <crc32>
2490 Where address/count indicate a memory area
2491 and crc32 is the correct crc32 which the
2495 Add the "loopw" memory command. This only takes effect if
2496 the memory commands are activated globally (CONFIG_CMD_MEM).
2499 Add the "mdc" and "mwc" memory commands. These are cyclic
2504 This command will print 4 bytes (10,11,12,13) each 500 ms.
2506 => mwc.l 100 12345678 10
2507 This command will write 12345678 to address 100 all 10 ms.
2509 This only takes effect if the memory commands are activated
2510 globally (CONFIG_CMD_MEM).
2512 - CONFIG_SKIP_LOWLEVEL_INIT
2513 - CONFIG_SKIP_RELOCATE_UBOOT
2515 [ARM only] If these variables are defined, then
2516 certain low level initializations (like setting up
2517 the memory controller) are omitted and/or U-Boot does
2518 not relocate itself into RAM.
2519 Normally these variables MUST NOT be defined. The
2520 only exception is when U-Boot is loaded (to RAM) by
2521 some other boot loader or by a debugger which
2522 performs these intializations itself.
2525 Building the Software:
2526 ======================
2528 Building U-Boot has been tested in several native build environments
2529 and in many different cross environments. Of course we cannot support
2530 all possibly existing versions of cross development tools in all
2531 (potentially obsolete) versions. In case of tool chain problems we
2532 recommend to use the ELDK (see http://www.denx.de/wiki/DULG/ELDK)
2533 which is extensively used to build and test U-Boot.
2535 If you are not using a native environment, it is assumed that you
2536 have GNU cross compiling tools available in your path. In this case,
2537 you must set the environment variable CROSS_COMPILE in your shell.
2538 Note that no changes to the Makefile or any other source files are
2539 necessary. For example using the ELDK on a 4xx CPU, please enter:
2541 $ CROSS_COMPILE=ppc_4xx-
2542 $ export CROSS_COMPILE
2544 U-Boot is intended to be simple to build. After installing the
2545 sources you must configure U-Boot for one specific board type. This
2550 where "NAME_config" is the name of one of the existing configu-
2551 rations; see the main Makefile for supported names.
2553 Note: for some board special configuration names may exist; check if
2554 additional information is available from the board vendor; for
2555 instance, the TQM823L systems are available without (standard)
2556 or with LCD support. You can select such additional "features"
2557 when chosing the configuration, i. e.
2560 - will configure for a plain TQM823L, i. e. no LCD support
2562 make TQM823L_LCD_config
2563 - will configure for a TQM823L with U-Boot console on LCD
2568 Finally, type "make all", and you should get some working U-Boot
2569 images ready for download to / installation on your system:
2571 - "u-boot.bin" is a raw binary image
2572 - "u-boot" is an image in ELF binary format
2573 - "u-boot.srec" is in Motorola S-Record format
2575 By default the build is performed locally and the objects are saved
2576 in the source directory. One of the two methods can be used to change
2577 this behavior and build U-Boot to some external directory:
2579 1. Add O= to the make command line invocations:
2581 make O=/tmp/build distclean
2582 make O=/tmp/build NAME_config
2583 make O=/tmp/build all
2585 2. Set environment variable BUILD_DIR to point to the desired location:
2587 export BUILD_DIR=/tmp/build
2592 Note that the command line "O=" setting overrides the BUILD_DIR environment
2596 Please be aware that the Makefiles assume you are using GNU make, so
2597 for instance on NetBSD you might need to use "gmake" instead of
2601 If the system board that you have is not listed, then you will need
2602 to port U-Boot to your hardware platform. To do this, follow these
2605 1. Add a new configuration option for your board to the toplevel
2606 "Makefile" and to the "MAKEALL" script, using the existing
2607 entries as examples. Note that here and at many other places
2608 boards and other names are listed in alphabetical sort order. Please
2610 2. Create a new directory to hold your board specific code. Add any
2611 files you need. In your board directory, you will need at least
2612 the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
2613 3. Create a new configuration file "include/configs/<board>.h" for
2615 3. If you're porting U-Boot to a new CPU, then also create a new
2616 directory to hold your CPU specific code. Add any files you need.
2617 4. Run "make <board>_config" with your new name.
2618 5. Type "make", and you should get a working "u-boot.srec" file
2619 to be installed on your target system.
2620 6. Debug and solve any problems that might arise.
2621 [Of course, this last step is much harder than it sounds.]
2624 Testing of U-Boot Modifications, Ports to New Hardware, etc.:
2625 ==============================================================
2627 If you have modified U-Boot sources (for instance added a new board
2628 or support for new devices, a new CPU, etc.) you are expected to
2629 provide feedback to the other developers. The feedback normally takes
2630 the form of a "patch", i. e. a context diff against a certain (latest
2631 official or latest in the git repository) version of U-Boot sources.
2633 But before you submit such a patch, please verify that your modifi-
2634 cation did not break existing code. At least make sure that *ALL* of
2635 the supported boards compile WITHOUT ANY compiler warnings. To do so,
2636 just run the "MAKEALL" script, which will configure and build U-Boot
2637 for ALL supported system. Be warned, this will take a while. You can
2638 select which (cross) compiler to use by passing a `CROSS_COMPILE'
2639 environment variable to the script, i. e. to use the ELDK cross tools
2642 CROSS_COMPILE=ppc_8xx- MAKEALL
2644 or to build on a native PowerPC system you can type
2646 CROSS_COMPILE=' ' MAKEALL
2648 When using the MAKEALL script, the default behaviour is to build
2649 U-Boot in the source directory. This location can be changed by
2650 setting the BUILD_DIR environment variable. Also, for each target
2651 built, the MAKEALL script saves two log files (<target>.ERR and
2652 <target>.MAKEALL) in the <source dir>/LOG directory. This default
2653 location can be changed by setting the MAKEALL_LOGDIR environment
2654 variable. For example:
2656 export BUILD_DIR=/tmp/build
2657 export MAKEALL_LOGDIR=/tmp/log
2658 CROSS_COMPILE=ppc_8xx- MAKEALL
2660 With the above settings build objects are saved in the /tmp/build,
2661 log files are saved in the /tmp/log and the source tree remains clean
2662 during the whole build process.
2665 See also "U-Boot Porting Guide" below.
2668 Monitor Commands - Overview:
2669 ============================
2671 go - start application at address 'addr'
2672 run - run commands in an environment variable
2673 bootm - boot application image from memory
2674 bootp - boot image via network using BootP/TFTP protocol
2675 tftpboot- boot image via network using TFTP protocol
2676 and env variables "ipaddr" and "serverip"
2677 (and eventually "gatewayip")
2678 rarpboot- boot image via network using RARP/TFTP protocol
2679 diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd'
2680 loads - load S-Record file over serial line
2681 loadb - load binary file over serial line (kermit mode)
2683 mm - memory modify (auto-incrementing)
2684 nm - memory modify (constant address)
2685 mw - memory write (fill)
2687 cmp - memory compare
2688 crc32 - checksum calculation
2689 imd - i2c memory display
2690 imm - i2c memory modify (auto-incrementing)
2691 inm - i2c memory modify (constant address)
2692 imw - i2c memory write (fill)
2693 icrc32 - i2c checksum calculation
2694 iprobe - probe to discover valid I2C chip addresses
2695 iloop - infinite loop on address range
2696 isdram - print SDRAM configuration information
2697 sspi - SPI utility commands
2698 base - print or set address offset
2699 printenv- print environment variables
2700 setenv - set environment variables
2701 saveenv - save environment variables to persistent storage
2702 protect - enable or disable FLASH write protection
2703 erase - erase FLASH memory
2704 flinfo - print FLASH memory information
2705 bdinfo - print Board Info structure
2706 iminfo - print header information for application image
2707 coninfo - print console devices and informations
2708 ide - IDE sub-system
2709 loop - infinite loop on address range
2710 loopw - infinite write loop on address range
2711 mtest - simple RAM test
2712 icache - enable or disable instruction cache
2713 dcache - enable or disable data cache
2714 reset - Perform RESET of the CPU
2715 echo - echo args to console
2716 version - print monitor version
2717 help - print online help
2718 ? - alias for 'help'
2721 Monitor Commands - Detailed Description:
2722 ========================================
2726 For now: just type "help <command>".
2729 Environment Variables:
2730 ======================
2732 U-Boot supports user configuration using Environment Variables which
2733 can be made persistent by saving to Flash memory.
2735 Environment Variables are set using "setenv", printed using
2736 "printenv", and saved to Flash using "saveenv". Using "setenv"
2737 without a value can be used to delete a variable from the
2738 environment. As long as you don't save the environment you are
2739 working with an in-memory copy. In case the Flash area containing the
2740 environment is erased by accident, a default environment is provided.
2742 Some configuration options can be set using Environment Variables:
2744 baudrate - see CONFIG_BAUDRATE
2746 bootdelay - see CONFIG_BOOTDELAY
2748 bootcmd - see CONFIG_BOOTCOMMAND
2750 bootargs - Boot arguments when booting an RTOS image
2752 bootfile - Name of the image to load with TFTP
2754 bootm_low - Memory range available for image processing in the bootm
2755 command can be restricted. This variable is given as
2756 a hexadecimal number and defines lowest address allowed
2757 for use by the bootm command. See also "bootm_size"
2758 environment variable. Address defined by "bootm_low" is
2759 also the base of the initial memory mapping for the Linux
2760 kernel -- see the descripton of CFG_BOOTMAPSZ.
2762 bootm_size - Memory range available for image processing in the bootm
2763 command can be restricted. This variable is given as
2764 a hexadecimal number and defines the size of the region
2765 allowed for use by the bootm command. See also "bootm_low"
2766 environment variable.
2768 autoload - if set to "no" (any string beginning with 'n'),
2769 "bootp" will just load perform a lookup of the
2770 configuration from the BOOTP server, but not try to
2771 load any image using TFTP
2773 autoscript - if set to "yes" commands like "loadb", "loady",
2774 "bootp", "tftpb", "rarpboot" and "nfs" will attempt
2775 to automatically run script images (by internally
2776 calling "autoscript").
2778 autoscript_uname - if script image is in a format (FIT) this
2779 variable is used to get script subimage unit name.
2781 autostart - if set to "yes", an image loaded using the "bootp",
2782 "rarpboot", "tftpboot" or "diskboot" commands will
2783 be automatically started (by internally calling
2786 If set to "no", a standalone image passed to the
2787 "bootm" command will be copied to the load address
2788 (and eventually uncompressed), but NOT be started.
2789 This can be used to load and uncompress arbitrary
2792 i2cfast - (PPC405GP|PPC405EP only)
2793 if set to 'y' configures Linux I2C driver for fast
2794 mode (400kHZ). This environment variable is used in
2795 initialization code. So, for changes to be effective
2796 it must be saved and board must be reset.
2798 initrd_high - restrict positioning of initrd images:
2799 If this variable is not set, initrd images will be
2800 copied to the highest possible address in RAM; this
2801 is usually what you want since it allows for
2802 maximum initrd size. If for some reason you want to
2803 make sure that the initrd image is loaded below the
2804 CFG_BOOTMAPSZ limit, you can set this environment
2805 variable to a value of "no" or "off" or "0".
2806 Alternatively, you can set it to a maximum upper
2807 address to use (U-Boot will still check that it
2808 does not overwrite the U-Boot stack and data).
2810 For instance, when you have a system with 16 MB
2811 RAM, and want to reserve 4 MB from use by Linux,
2812 you can do this by adding "mem=12M" to the value of
2813 the "bootargs" variable. However, now you must make
2814 sure that the initrd image is placed in the first
2815 12 MB as well - this can be done with
2817 setenv initrd_high 00c00000
2819 If you set initrd_high to 0xFFFFFFFF, this is an
2820 indication to U-Boot that all addresses are legal
2821 for the Linux kernel, including addresses in flash
2822 memory. In this case U-Boot will NOT COPY the
2823 ramdisk at all. This may be useful to reduce the
2824 boot time on your system, but requires that this
2825 feature is supported by your Linux kernel.
2827 ipaddr - IP address; needed for tftpboot command
2829 loadaddr - Default load address for commands like "bootp",
2830 "rarpboot", "tftpboot", "loadb" or "diskboot"
2832 loads_echo - see CONFIG_LOADS_ECHO
2834 serverip - TFTP server IP address; needed for tftpboot command
2836 bootretry - see CONFIG_BOOT_RETRY_TIME
2838 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR
2840 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR
2842 ethprime - When CONFIG_NET_MULTI is enabled controls which
2843 interface is used first.
2845 ethact - When CONFIG_NET_MULTI is enabled controls which
2846 interface is currently active. For example you
2847 can do the following
2849 => setenv ethact FEC ETHERNET
2850 => ping 192.168.0.1 # traffic sent on FEC ETHERNET
2851 => setenv ethact SCC ETHERNET
2852 => ping 10.0.0.1 # traffic sent on SCC ETHERNET
2854 ethrotate - When set to "no" U-Boot does not go through all
2855 available network interfaces.
2856 It just stays at the currently selected interface.
2858 netretry - When set to "no" each network operation will
2859 either succeed or fail without retrying.
2860 When set to "once" the network operation will
2861 fail when all the available network interfaces
2862 are tried once without success.
2863 Useful on scripts which control the retry operation
2866 npe_ucode - see CONFIG_IXP4XX_NPE_EXT_UCOD
2867 if set load address for the npe microcode
2869 tftpsrcport - If this is set, the value is used for TFTP's
2872 tftpdstport - If this is set, the value is used for TFTP's UDP
2873 destination port instead of the Well Know Port 69.
2875 vlan - When set to a value < 4095 the traffic over
2876 ethernet is encapsulated/received over 802.1q
2879 The following environment variables may be used and automatically
2880 updated by the network boot commands ("bootp" and "rarpboot"),
2881 depending the information provided by your boot server:
2883 bootfile - see above
2884 dnsip - IP address of your Domain Name Server
2885 dnsip2 - IP address of your secondary Domain Name Server
2886 gatewayip - IP address of the Gateway (Router) to use
2887 hostname - Target hostname
2889 netmask - Subnet Mask
2890 rootpath - Pathname of the root filesystem on the NFS server
2891 serverip - see above
2894 There are two special Environment Variables:
2896 serial# - contains hardware identification information such
2897 as type string and/or serial number
2898 ethaddr - Ethernet address
2900 These variables can be set only once (usually during manufacturing of
2901 the board). U-Boot refuses to delete or overwrite these variables
2902 once they have been set once.
2905 Further special Environment Variables:
2907 ver - Contains the U-Boot version string as printed
2908 with the "version" command. This variable is
2909 readonly (see CONFIG_VERSION_VARIABLE).
2912 Please note that changes to some configuration parameters may take
2913 only effect after the next boot (yes, that's just like Windoze :-).
2916 Command Line Parsing:
2917 =====================
2919 There are two different command line parsers available with U-Boot:
2920 the old "simple" one, and the much more powerful "hush" shell:
2922 Old, simple command line parser:
2923 --------------------------------
2925 - supports environment variables (through setenv / saveenv commands)
2926 - several commands on one line, separated by ';'
2927 - variable substitution using "... ${name} ..." syntax
2928 - special characters ('$', ';') can be escaped by prefixing with '\',
2930 setenv bootcmd bootm \${address}
2931 - You can also escape text by enclosing in single apostrophes, for example:
2932 setenv addip 'setenv bootargs $bootargs ip=$ipaddr:$serverip:$gatewayip:$netmask:$hostname::off'
2937 - similar to Bourne shell, with control structures like
2938 if...then...else...fi, for...do...done; while...do...done,
2939 until...do...done, ...
2940 - supports environment ("global") variables (through setenv / saveenv
2941 commands) and local shell variables (through standard shell syntax
2942 "name=value"); only environment variables can be used with "run"
2948 (1) If a command line (or an environment variable executed by a "run"
2949 command) contains several commands separated by semicolon, and
2950 one of these commands fails, then the remaining commands will be
2953 (2) If you execute several variables with one call to run (i. e.
2954 calling run with a list af variables as arguments), any failing
2955 command will cause "run" to terminate, i. e. the remaining
2956 variables are not executed.
2958 Note for Redundant Ethernet Interfaces:
2959 =======================================
2961 Some boards come with redundant ethernet interfaces; U-Boot supports
2962 such configurations and is capable of automatic selection of a
2963 "working" interface when needed. MAC assignment works as follows:
2965 Network interfaces are numbered eth0, eth1, eth2, ... Corresponding
2966 MAC addresses can be stored in the environment as "ethaddr" (=>eth0),
2967 "eth1addr" (=>eth1), "eth2addr", ...
2969 If the network interface stores some valid MAC address (for instance
2970 in SROM), this is used as default address if there is NO correspon-
2971 ding setting in the environment; if the corresponding environment
2972 variable is set, this overrides the settings in the card; that means:
2974 o If the SROM has a valid MAC address, and there is no address in the
2975 environment, the SROM's address is used.
2977 o If there is no valid address in the SROM, and a definition in the
2978 environment exists, then the value from the environment variable is
2981 o If both the SROM and the environment contain a MAC address, and
2982 both addresses are the same, this MAC address is used.
2984 o If both the SROM and the environment contain a MAC address, and the
2985 addresses differ, the value from the environment is used and a
2988 o If neither SROM nor the environment contain a MAC address, an error
2995 U-Boot is capable of booting (and performing other auxiliary operations on)
2996 images in two formats:
2998 New uImage format (FIT)
2999 -----------------------
3001 Flexible and powerful format based on Flattened Image Tree -- FIT (similar
3002 to Flattened Device Tree). It allows the use of images with multiple
3003 components (several kernels, ramdisks, etc.), with contents protected by
3004 SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory.
3010 Old image format is based on binary files which can be basically anything,
3011 preceded by a special header; see the definitions in include/image.h for
3012 details; basically, the header defines the following image properties:
3014 * Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD,
3015 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks,
3016 LynxOS, pSOS, QNX, RTEMS, ARTOS;
3017 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, ARTOS, LynxOS).
3018 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
3019 IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
3020 Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
3021 * Compression Type (uncompressed, gzip, bzip2)
3027 The header is marked by a special Magic Number, and both the header
3028 and the data portions of the image are secured against corruption by
3035 Although U-Boot should support any OS or standalone application
3036 easily, the main focus has always been on Linux during the design of
3039 U-Boot includes many features that so far have been part of some
3040 special "boot loader" code within the Linux kernel. Also, any
3041 "initrd" images to be used are no longer part of one big Linux image;
3042 instead, kernel and "initrd" are separate images. This implementation
3043 serves several purposes:
3045 - the same features can be used for other OS or standalone
3046 applications (for instance: using compressed images to reduce the
3047 Flash memory footprint)
3049 - it becomes much easier to port new Linux kernel versions because
3050 lots of low-level, hardware dependent stuff are done by U-Boot
3052 - the same Linux kernel image can now be used with different "initrd"
3053 images; of course this also means that different kernel images can
3054 be run with the same "initrd". This makes testing easier (you don't
3055 have to build a new "zImage.initrd" Linux image when you just
3056 change a file in your "initrd"). Also, a field-upgrade of the
3057 software is easier now.
3063 Porting Linux to U-Boot based systems:
3064 ---------------------------------------
3066 U-Boot cannot save you from doing all the necessary modifications to
3067 configure the Linux device drivers for use with your target hardware
3068 (no, we don't intend to provide a full virtual machine interface to
3071 But now you can ignore ALL boot loader code (in arch/ppc/mbxboot).
3073 Just make sure your machine specific header file (for instance
3074 include/asm-ppc/tqm8xx.h) includes the same definition of the Board
3075 Information structure as we define in include/u-boot.h, and make
3076 sure that your definition of IMAP_ADDR uses the same value as your
3077 U-Boot configuration in CFG_IMMR.
3080 Configuring the Linux kernel:
3081 -----------------------------
3083 No specific requirements for U-Boot. Make sure you have some root
3084 device (initial ramdisk, NFS) for your target system.
3087 Building a Linux Image:
3088 -----------------------
3090 With U-Boot, "normal" build targets like "zImage" or "bzImage" are
3091 not used. If you use recent kernel source, a new build target
3092 "uImage" will exist which automatically builds an image usable by
3093 U-Boot. Most older kernels also have support for a "pImage" target,
3094 which was introduced for our predecessor project PPCBoot and uses a
3095 100% compatible format.
3104 The "uImage" build target uses a special tool (in 'tools/mkimage') to
3105 encapsulate a compressed Linux kernel image with header information,
3106 CRC32 checksum etc. for use with U-Boot. This is what we are doing:
3108 * build a standard "vmlinux" kernel image (in ELF binary format):
3110 * convert the kernel into a raw binary image:
3112 ${CROSS_COMPILE}-objcopy -O binary \
3113 -R .note -R .comment \
3114 -S vmlinux linux.bin
3116 * compress the binary image:
3120 * package compressed binary image for U-Boot:
3122 mkimage -A ppc -O linux -T kernel -C gzip \
3123 -a 0 -e 0 -n "Linux Kernel Image" \
3124 -d linux.bin.gz uImage
3127 The "mkimage" tool can also be used to create ramdisk images for use
3128 with U-Boot, either separated from the Linux kernel image, or
3129 combined into one file. "mkimage" encapsulates the images with a 64
3130 byte header containing information about target architecture,
3131 operating system, image type, compression method, entry points, time
3132 stamp, CRC32 checksums, etc.
3134 "mkimage" can be called in two ways: to verify existing images and
3135 print the header information, or to build new images.
3137 In the first form (with "-l" option) mkimage lists the information
3138 contained in the header of an existing U-Boot image; this includes
3139 checksum verification:
3141 tools/mkimage -l image
3142 -l ==> list image header information
3144 The second form (with "-d" option) is used to build a U-Boot image
3145 from a "data file" which is used as image payload:
3147 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \
3148 -n name -d data_file image
3149 -A ==> set architecture to 'arch'
3150 -O ==> set operating system to 'os'
3151 -T ==> set image type to 'type'
3152 -C ==> set compression type 'comp'
3153 -a ==> set load address to 'addr' (hex)
3154 -e ==> set entry point to 'ep' (hex)
3155 -n ==> set image name to 'name'
3156 -d ==> use image data from 'datafile'
3158 Right now, all Linux kernels for PowerPC systems use the same load
3159 address (0x00000000), but the entry point address depends on the
3162 - 2.2.x kernels have the entry point at 0x0000000C,
3163 - 2.3.x and later kernels have the entry point at 0x00000000.
3165 So a typical call to build a U-Boot image would read:
3167 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3168 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \
3169 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz \
3170 > examples/uImage.TQM850L
3171 Image Name: 2.4.4 kernel for TQM850L
3172 Created: Wed Jul 19 02:34:59 2000
3173 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3174 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3175 Load Address: 0x00000000
3176 Entry Point: 0x00000000
3178 To verify the contents of the image (or check for corruption):
3180 -> tools/mkimage -l examples/uImage.TQM850L
3181 Image Name: 2.4.4 kernel for TQM850L
3182 Created: Wed Jul 19 02:34:59 2000
3183 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3184 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB
3185 Load Address: 0x00000000
3186 Entry Point: 0x00000000
3188 NOTE: for embedded systems where boot time is critical you can trade
3189 speed for memory and install an UNCOMPRESSED image instead: this
3190 needs more space in Flash, but boots much faster since it does not
3191 need to be uncompressed:
3193 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux.gz
3194 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \
3195 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \
3196 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/ppc/coffboot/vmlinux \
3197 > examples/uImage.TQM850L-uncompressed
3198 Image Name: 2.4.4 kernel for TQM850L
3199 Created: Wed Jul 19 02:34:59 2000
3200 Image Type: PowerPC Linux Kernel Image (uncompressed)
3201 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB
3202 Load Address: 0x00000000
3203 Entry Point: 0x00000000
3206 Similar you can build U-Boot images from a 'ramdisk.image.gz' file
3207 when your kernel is intended to use an initial ramdisk:
3209 -> tools/mkimage -n 'Simple Ramdisk Image' \
3210 > -A ppc -O linux -T ramdisk -C gzip \
3211 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd
3212 Image Name: Simple Ramdisk Image
3213 Created: Wed Jan 12 14:01:50 2000
3214 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3215 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB
3216 Load Address: 0x00000000
3217 Entry Point: 0x00000000
3220 Installing a Linux Image:
3221 -------------------------
3223 To downloading a U-Boot image over the serial (console) interface,
3224 you must convert the image to S-Record format:
3226 objcopy -I binary -O srec examples/image examples/image.srec
3228 The 'objcopy' does not understand the information in the U-Boot
3229 image header, so the resulting S-Record file will be relative to
3230 address 0x00000000. To load it to a given address, you need to
3231 specify the target address as 'offset' parameter with the 'loads'
3234 Example: install the image to address 0x40100000 (which on the
3235 TQM8xxL is in the first Flash bank):
3237 => erase 40100000 401FFFFF
3243 ## Ready for S-Record download ...
3244 ~>examples/image.srec
3245 1 2 3 4 5 6 7 8 9 10 11 12 13 ...
3247 15989 15990 15991 15992
3248 [file transfer complete]
3250 ## Start Addr = 0x00000000
3253 You can check the success of the download using the 'iminfo' command;
3254 this includes a checksum verification so you can be sure no data
3255 corruption happened:
3259 ## Checking Image at 40100000 ...
3260 Image Name: 2.2.13 for initrd on TQM850L
3261 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3262 Data Size: 335725 Bytes = 327 kB = 0 MB
3263 Load Address: 00000000
3264 Entry Point: 0000000c
3265 Verifying Checksum ... OK
3271 The "bootm" command is used to boot an application that is stored in
3272 memory (RAM or Flash). In case of a Linux kernel image, the contents
3273 of the "bootargs" environment variable is passed to the kernel as
3274 parameters. You can check and modify this variable using the
3275 "printenv" and "setenv" commands:
3278 => printenv bootargs
3279 bootargs=root=/dev/ram
3281 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3283 => printenv bootargs
3284 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3287 ## Booting Linux kernel at 40020000 ...
3288 Image Name: 2.2.13 for NFS on TQM850L
3289 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3290 Data Size: 381681 Bytes = 372 kB = 0 MB
3291 Load Address: 00000000
3292 Entry Point: 0000000c
3293 Verifying Checksum ... OK
3294 Uncompressing Kernel Image ... OK
3295 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000
3296 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2
3297 time_init: decrementer frequency = 187500000/60
3298 Calibrating delay loop... 49.77 BogoMIPS
3299 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000]
3302 If you want to boot a Linux kernel with initial ram disk, you pass
3303 the memory addresses of both the kernel and the initrd image (PPBCOOT
3304 format!) to the "bootm" command:
3306 => imi 40100000 40200000
3308 ## Checking Image at 40100000 ...
3309 Image Name: 2.2.13 for initrd on TQM850L
3310 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3311 Data Size: 335725 Bytes = 327 kB = 0 MB
3312 Load Address: 00000000
3313 Entry Point: 0000000c
3314 Verifying Checksum ... OK
3316 ## Checking Image at 40200000 ...
3317 Image Name: Simple Ramdisk Image
3318 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3319 Data Size: 566530 Bytes = 553 kB = 0 MB
3320 Load Address: 00000000
3321 Entry Point: 00000000
3322 Verifying Checksum ... OK
3324 => bootm 40100000 40200000
3325 ## Booting Linux kernel at 40100000 ...
3326 Image Name: 2.2.13 for initrd on TQM850L
3327 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3328 Data Size: 335725 Bytes = 327 kB = 0 MB
3329 Load Address: 00000000
3330 Entry Point: 0000000c
3331 Verifying Checksum ... OK
3332 Uncompressing Kernel Image ... OK
3333 ## Loading RAMDisk Image at 40200000 ...
3334 Image Name: Simple Ramdisk Image
3335 Image Type: PowerPC Linux RAMDisk Image (gzip compressed)
3336 Data Size: 566530 Bytes = 553 kB = 0 MB
3337 Load Address: 00000000
3338 Entry Point: 00000000
3339 Verifying Checksum ... OK
3340 Loading Ramdisk ... OK
3341 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000
3342 Boot arguments: root=/dev/ram
3343 time_init: decrementer frequency = 187500000/60
3344 Calibrating delay loop... 49.77 BogoMIPS
3346 RAMDISK: Compressed image found at block 0
3347 VFS: Mounted root (ext2 filesystem).
3351 Boot Linux and pass a flat device tree:
3354 First, U-Boot must be compiled with the appropriate defines. See the section
3355 titled "Linux Kernel Interface" above for a more in depth explanation. The
3356 following is an example of how to start a kernel and pass an updated
3362 oft=oftrees/mpc8540ads.dtb
3363 => tftp $oftaddr $oft
3364 Speed: 1000, full duplex
3366 TFTP from server 192.168.1.1; our IP address is 192.168.1.101
3367 Filename 'oftrees/mpc8540ads.dtb'.
3368 Load address: 0x300000
3371 Bytes transferred = 4106 (100a hex)
3372 => tftp $loadaddr $bootfile
3373 Speed: 1000, full duplex
3375 TFTP from server 192.168.1.1; our IP address is 192.168.1.2
3377 Load address: 0x200000
3378 Loading:############
3380 Bytes transferred = 1029407 (fb51f hex)
3385 => bootm $loadaddr - $oftaddr
3386 ## Booting image at 00200000 ...
3387 Image Name: Linux-2.6.17-dirty
3388 Image Type: PowerPC Linux Kernel Image (gzip compressed)
3389 Data Size: 1029343 Bytes = 1005.2 kB
3390 Load Address: 00000000
3391 Entry Point: 00000000
3392 Verifying Checksum ... OK
3393 Uncompressing Kernel Image ... OK
3394 Booting using flat device tree at 0x300000
3395 Using MPC85xx ADS machine description
3396 Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
3400 More About U-Boot Image Types:
3401 ------------------------------
3403 U-Boot supports the following image types:
3405 "Standalone Programs" are directly runnable in the environment
3406 provided by U-Boot; it is expected that (if they behave
3407 well) you can continue to work in U-Boot after return from
3408 the Standalone Program.
3409 "OS Kernel Images" are usually images of some Embedded OS which
3410 will take over control completely. Usually these programs
3411 will install their own set of exception handlers, device
3412 drivers, set up the MMU, etc. - this means, that you cannot
3413 expect to re-enter U-Boot except by resetting the CPU.
3414 "RAMDisk Images" are more or less just data blocks, and their
3415 parameters (address, size) are passed to an OS kernel that is
3417 "Multi-File Images" contain several images, typically an OS
3418 (Linux) kernel image and one or more data images like
3419 RAMDisks. This construct is useful for instance when you want
3420 to boot over the network using BOOTP etc., where the boot
3421 server provides just a single image file, but you want to get
3422 for instance an OS kernel and a RAMDisk image.
3424 "Multi-File Images" start with a list of image sizes, each
3425 image size (in bytes) specified by an "uint32_t" in network
3426 byte order. This list is terminated by an "(uint32_t)0".
3427 Immediately after the terminating 0 follow the images, one by
3428 one, all aligned on "uint32_t" boundaries (size rounded up to
3429 a multiple of 4 bytes).
3431 "Firmware Images" are binary images containing firmware (like
3432 U-Boot or FPGA images) which usually will be programmed to
3435 "Script files" are command sequences that will be executed by
3436 U-Boot's command interpreter; this feature is especially
3437 useful when you configure U-Boot to use a real shell (hush)
3438 as command interpreter.
3444 One of the features of U-Boot is that you can dynamically load and
3445 run "standalone" applications, which can use some resources of
3446 U-Boot like console I/O functions or interrupt services.
3448 Two simple examples are included with the sources:
3453 'examples/hello_world.c' contains a small "Hello World" Demo
3454 application; it is automatically compiled when you build U-Boot.
3455 It's configured to run at address 0x00040004, so you can play with it
3459 ## Ready for S-Record download ...
3460 ~>examples/hello_world.srec
3461 1 2 3 4 5 6 7 8 9 10 11 ...
3462 [file transfer complete]
3464 ## Start Addr = 0x00040004
3466 => go 40004 Hello World! This is a test.
3467 ## Starting application at 0x00040004 ...
3478 Hit any key to exit ...
3480 ## Application terminated, rc = 0x0
3482 Another example, which demonstrates how to register a CPM interrupt
3483 handler with the U-Boot code, can be found in 'examples/timer.c'.
3484 Here, a CPM timer is set up to generate an interrupt every second.
3485 The interrupt service routine is trivial, just printing a '.'
3486 character, but this is just a demo program. The application can be
3487 controlled by the following keys:
3489 ? - print current values og the CPM Timer registers
3490 b - enable interrupts and start timer
3491 e - stop timer and disable interrupts
3492 q - quit application
3495 ## Ready for S-Record download ...
3496 ~>examples/timer.srec
3497 1 2 3 4 5 6 7 8 9 10 11 ...
3498 [file transfer complete]
3500 ## Start Addr = 0x00040004
3503 ## Starting application at 0x00040004 ...
3506 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0
3509 [q, b, e, ?] Set interval 1000000 us
3512 [q, b, e, ?] ........
3513 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0
3516 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0
3519 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0
3522 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0
3524 [q, b, e, ?] ...Stopping timer
3526 [q, b, e, ?] ## Application terminated, rc = 0x0
3532 Over time, many people have reported problems when trying to use the
3533 "minicom" terminal emulation program for serial download. I (wd)
3534 consider minicom to be broken, and recommend not to use it. Under
3535 Unix, I recommend to use C-Kermit for general purpose use (and
3536 especially for kermit binary protocol download ("loadb" command), and
3537 use "cu" for S-Record download ("loads" command).
3539 Nevertheless, if you absolutely want to use it try adding this
3540 configuration to your "File transfer protocols" section:
3542 Name Program Name U/D FullScr IO-Red. Multi
3543 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N
3544 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N
3550 Starting at version 0.9.2, U-Boot supports NetBSD both as host
3551 (build U-Boot) and target system (boots NetBSD/mpc8xx).
3553 Building requires a cross environment; it is known to work on
3554 NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also
3555 need gmake since the Makefiles are not compatible with BSD make).
3556 Note that the cross-powerpc package does not install include files;
3557 attempting to build U-Boot will fail because <machine/ansi.h> is
3558 missing. This file has to be installed and patched manually:
3560 # cd /usr/pkg/cross/powerpc-netbsd/include
3562 # ln -s powerpc machine
3563 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h
3564 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST
3566 Native builds *don't* work due to incompatibilities between native
3567 and U-Boot include files.
3569 Booting assumes that (the first part of) the image booted is a
3570 stage-2 loader which in turn loads and then invokes the kernel
3571 proper. Loader sources will eventually appear in the NetBSD source
3572 tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the
3573 meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz
3576 Implementation Internals:
3577 =========================
3579 The following is not intended to be a complete description of every
3580 implementation detail. However, it should help to understand the
3581 inner workings of U-Boot and make it easier to port it to custom
3585 Initial Stack, Global Data:
3586 ---------------------------
3588 The implementation of U-Boot is complicated by the fact that U-Boot
3589 starts running out of ROM (flash memory), usually without access to
3590 system RAM (because the memory controller is not initialized yet).
3591 This means that we don't have writable Data or BSS segments, and BSS
3592 is not initialized as zero. To be able to get a C environment working
3593 at all, we have to allocate at least a minimal stack. Implementation
3594 options for this are defined and restricted by the CPU used: Some CPU
3595 models provide on-chip memory (like the IMMR area on MPC8xx and
3596 MPC826x processors), on others (parts of) the data cache can be
3597 locked as (mis-) used as memory, etc.
3599 Chris Hallinan posted a good summary of these issues to the
3600 u-boot-users mailing list:
3602 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)?
3603 From: "Chris Hallinan" <clh@net1plus.com>
3604 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET)
3607 Correct me if I'm wrong, folks, but the way I understand it
3608 is this: Using DCACHE as initial RAM for Stack, etc, does not
3609 require any physical RAM backing up the cache. The cleverness
3610 is that the cache is being used as a temporary supply of
3611 necessary storage before the SDRAM controller is setup. It's
3612 beyond the scope of this list to expain the details, but you
3613 can see how this works by studying the cache architecture and
3614 operation in the architecture and processor-specific manuals.
3616 OCM is On Chip Memory, which I believe the 405GP has 4K. It
3617 is another option for the system designer to use as an
3618 initial stack/ram area prior to SDRAM being available. Either
3619 option should work for you. Using CS 4 should be fine if your
3620 board designers haven't used it for something that would
3621 cause you grief during the initial boot! It is frequently not
3624 CFG_INIT_RAM_ADDR should be somewhere that won't interfere
3625 with your processor/board/system design. The default value
3626 you will find in any recent u-boot distribution in
3627 walnut.h should work for you. I'd set it to a value larger
3628 than your SDRAM module. If you have a 64MB SDRAM module, set
3629 it above 400_0000. Just make sure your board has no resources
3630 that are supposed to respond to that address! That code in
3631 start.S has been around a while and should work as is when
3632 you get the config right.
3637 It is essential to remember this, since it has some impact on the C
3638 code for the initialization procedures:
3640 * Initialized global data (data segment) is read-only. Do not attempt
3643 * Do not use any unitialized global data (or implicitely initialized
3644 as zero data - BSS segment) at all - this is undefined, initiali-
3645 zation is performed later (when relocating to RAM).
3647 * Stack space is very limited. Avoid big data buffers or things like
3650 Having only the stack as writable memory limits means we cannot use
3651 normal global data to share information beween the code. But it
3652 turned out that the implementation of U-Boot can be greatly
3653 simplified by making a global data structure (gd_t) available to all
3654 functions. We could pass a pointer to this data as argument to _all_
3655 functions, but this would bloat the code. Instead we use a feature of
3656 the GCC compiler (Global Register Variables) to share the data: we
3657 place a pointer (gd) to the global data into a register which we
3658 reserve for this purpose.
3660 When choosing a register for such a purpose we are restricted by the
3661 relevant (E)ABI specifications for the current architecture, and by
3662 GCC's implementation.
3664 For PowerPC, the following registers have specific use:
3666 R2: reserved for system use
3667 R3-R4: parameter passing and return values
3668 R5-R10: parameter passing
3669 R13: small data area pointer
3673 (U-Boot also uses R14 as internal GOT pointer.)
3675 ==> U-Boot will use R2 to hold a pointer to the global data
3677 Note: on PPC, we could use a static initializer (since the
3678 address of the global data structure is known at compile time),
3679 but it turned out that reserving a register results in somewhat
3680 smaller code - although the code savings are not that big (on
3681 average for all boards 752 bytes for the whole U-Boot image,
3682 624 text + 127 data).
3684 On Blackfin, the normal C ABI (except for P5) is followed as documented here:
3685 http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
3687 ==> U-Boot will use P5 to hold a pointer to the global data
3689 On ARM, the following registers are used:
3691 R0: function argument word/integer result
3692 R1-R3: function argument word
3694 R10: stack limit (used only if stack checking if enabled)
3695 R11: argument (frame) pointer
3696 R12: temporary workspace
3699 R15: program counter
3701 ==> U-Boot will use R8 to hold a pointer to the global data
3703 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
3704 or current versions of GCC may "optimize" the code too much.
3709 U-Boot runs in system state and uses physical addresses, i.e. the
3710 MMU is not used either for address mapping nor for memory protection.
3712 The available memory is mapped to fixed addresses using the memory
3713 controller. In this process, a contiguous block is formed for each
3714 memory type (Flash, SDRAM, SRAM), even when it consists of several
3715 physical memory banks.
3717 U-Boot is installed in the first 128 kB of the first Flash bank (on
3718 TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
3719 booting and sizing and initializing DRAM, the code relocates itself
3720 to the upper end of DRAM. Immediately below the U-Boot code some
3721 memory is reserved for use by malloc() [see CFG_MALLOC_LEN
3722 configuration setting]. Below that, a structure with global Board
3723 Info data is placed, followed by the stack (growing downward).
3725 Additionally, some exception handler code is copied to the low 8 kB
3726 of DRAM (0x00000000 ... 0x00001FFF).
3728 So a typical memory configuration with 16 MB of DRAM could look like
3731 0x0000 0000 Exception Vector code
3734 0x0000 2000 Free for Application Use
3740 0x00FB FF20 Monitor Stack (Growing downward)
3741 0x00FB FFAC Board Info Data and permanent copy of global data
3742 0x00FC 0000 Malloc Arena
3745 0x00FE 0000 RAM Copy of Monitor Code
3746 ... eventually: LCD or video framebuffer
3747 ... eventually: pRAM (Protected RAM - unchanged by reset)
3748 0x00FF FFFF [End of RAM]
3751 System Initialization:
3752 ----------------------
3754 In the reset configuration, U-Boot starts at the reset entry point
3755 (on most PowerPC systens at address 0x00000100). Because of the reset
3756 configuration for CS0# this is a mirror of the onboard Flash memory.
3757 To be able to re-map memory U-Boot then jumps to its link address.
3758 To be able to implement the initialization code in C, a (small!)
3759 initial stack is set up in the internal Dual Ported RAM (in case CPUs
3760 which provide such a feature like MPC8xx or MPC8260), or in a locked
3761 part of the data cache. After that, U-Boot initializes the CPU core,
3762 the caches and the SIU.
3764 Next, all (potentially) available memory banks are mapped using a
3765 preliminary mapping. For example, we put them on 512 MB boundaries
3766 (multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash
3767 on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is
3768 programmed for SDRAM access. Using the temporary configuration, a
3769 simple memory test is run that determines the size of the SDRAM
3772 When there is more than one SDRAM bank, and the banks are of
3773 different size, the largest is mapped first. For equal size, the first
3774 bank (CS2#) is mapped first. The first mapping is always for address
3775 0x00000000, with any additional banks following immediately to create
3776 contiguous memory starting from 0.
3778 Then, the monitor installs itself at the upper end of the SDRAM area
3779 and allocates memory for use by malloc() and for the global Board
3780 Info data; also, the exception vector code is copied to the low RAM
3781 pages, and the final stack is set up.
3783 Only after this relocation will you have a "normal" C environment;
3784 until that you are restricted in several ways, mostly because you are
3785 running from ROM, and because the code will have to be relocated to a
3789 U-Boot Porting Guide:
3790 ----------------------
3792 [Based on messages by Jerry Van Baren in the U-Boot-Users mailing
3796 int main (int argc, char *argv[])
3798 sighandler_t no_more_time;
3800 signal (SIGALRM, no_more_time);
3801 alarm (PROJECT_DEADLINE - toSec (3 * WEEK));
3803 if (available_money > available_manpower) {
3804 pay consultant to port U-Boot;
3808 Download latest U-Boot source;
3810 Subscribe to u-boot-users mailing list;
3813 email ("Hi, I am new to U-Boot, how do I get started?");
3817 Read the README file in the top level directory;
3818 Read http://www.denx.de/twiki/bin/view/DULG/Manual ;
3819 Read the source, Luke;
3822 if (available_money > toLocalCurrency ($2500)) {
3825 Add a lot of aggravation and time;
3828 Create your own board support subdirectory;
3830 Create your own board config file;
3834 Add / modify source code;
3838 email ("Hi, I am having problems...");
3840 Send patch file to Wolfgang;
3845 void no_more_time (int sig)
3854 All contributions to U-Boot should conform to the Linux kernel
3855 coding style; see the file "Documentation/CodingStyle" and the script
3856 "scripts/Lindent" in your Linux kernel source directory. In sources
3857 originating from U-Boot a style corresponding to "Lindent -pcs" (adding
3858 spaces before parameters to function calls) is actually used.
3860 Source files originating from a different project (for example the
3861 MTD subsystem) are generally exempt from these guidelines and are not
3862 reformated to ease subsequent migration to newer versions of those
3865 Please note that U-Boot is implemented in C (and to some small parts in
3866 Assembler); no C++ is used, so please do not use C++ style comments (//)
3869 Please also stick to the following formatting rules:
3870 - remove any trailing white space
3871 - use TAB characters for indentation, not spaces
3872 - make sure NOT to use DOS '\r\n' line feeds
3873 - do not add more than 2 empty lines to source files
3874 - do not add trailing empty lines to source files
3876 Submissions which do not conform to the standards may be returned
3877 with a request to reformat the changes.
3883 Since the number of patches for U-Boot is growing, we need to
3884 establish some rules. Submissions which do not conform to these rules
3885 may be rejected, even when they contain important and valuable stuff.
3887 Patches shall be sent to the u-boot-users mailing list.
3889 Please see http://www.denx.de/wiki/UBoot/Patches for details.
3891 When you send a patch, please include the following information with
3894 * For bug fixes: a description of the bug and how your patch fixes
3895 this bug. Please try to include a way of demonstrating that the
3896 patch actually fixes something.
3898 * For new features: a description of the feature and your
3901 * A CHANGELOG entry as plaintext (separate from the patch)
3903 * For major contributions, your entry to the CREDITS file
3905 * When you add support for a new board, don't forget to add this
3906 board to the MAKEALL script, too.
3908 * If your patch adds new configuration options, don't forget to
3909 document these in the README file.
3911 * The patch itself. If you are using git (which is *strongly*
3912 recommended) you can easily generate the patch using the
3913 "git-format-patch". If you then use "git-send-email" to send it to
3914 the U-Boot mailing list, you will avoid most of the common problems
3915 with some other mail clients.
3917 If you cannot use git, use "diff -purN OLD NEW". If your version of
3918 diff does not support these options, then get the latest version of
3921 The current directory when running this command shall be the parent
3922 directory of the U-Boot source tree (i. e. please make sure that
3923 your patch includes sufficient directory information for the
3926 We prefer patches as plain text. MIME attachments are discouraged,
3927 and compressed attachments must not be used.
3929 * If one logical set of modifications affects or creates several
3930 files, all these changes shall be submitted in a SINGLE patch file.
3932 * Changesets that contain different, unrelated modifications shall be
3933 submitted as SEPARATE patches, one patch per changeset.
3938 * Before sending the patch, run the MAKEALL script on your patched
3939 source tree and make sure that no errors or warnings are reported
3940 for any of the boards.
3942 * Keep your modifications to the necessary minimum: A patch
3943 containing several unrelated changes or arbitrary reformats will be
3944 returned with a request to re-formatting / split it.
3946 * If you modify existing code, make sure that your new code does not
3947 add to the memory footprint of the code ;-) Small is beautiful!
3948 When adding new features, these should compile conditionally only
3949 (using #ifdef), and the resulting code with the new feature
3950 disabled must not need more memory than the old code without your
3953 * Remember that there is a size limit of 40 kB per message on the
3954 u-boot-users mailing list. Bigger patches will be moderated. If
3955 they are reasonable and not bigger than 100 kB, they will be
3956 acknowledged. Even bigger patches should be avoided.
projects / people / ms / u-boot.git / blob